China summoned Japanese and Philippine diplomats on Friday to express dissatisfaction over negative comments about it aired during a summit of the leaders of the United States, Japan and Philippines, the foreign ministry said.

The United States and its allies, including Japan, have been building up their militaries to counter what they see as a growing threat from China in areas such as the busy waterway of the South China Sea and around Taiwan.

At this week's summit in Washington, the three leaders discussed China's aggressive actions in the disputed South China Sea, besides unveiling a wide range of pacts to boost security and economic ties.

"We strongly deplore and strongly oppose the remarks," a foreign ministry spokesperson, Mao Ning, told a regular press briefing in response to Japanese Prime Minister Fumio Kishida's speech to U.S. Congress in which he named China the biggest challenge the world.

China strongly opposes these countries' small-group politics and any acts that instigate and drive up tension, she said about the summit.

"China opposes forming exclusive circles in the region," Mao said.

A ministry official, Liu Jinsong, met a Japanese embassy official, Akira Yokochi, to make "solemn representations" about the negative comments, the ministry said in a statement, voicing China's serious concern and strong dissatisfaction.

Liu also made "solemn representations" to the Philippine ambassador to China Jaime FlorCruz, who was summoned by the ministry over the Southeast Asian country's "negative words and deeds" related to China during the summit.

U.S. President Joe Biden and Kishida had laid out a series of projects, from codeveloping missiles to manned moon landings, while condemning China's escalatory behavior in the South China Sea region.

The two also announced plans to upgrade their military alliance, including the U.S. military command in Japan and more joint development of defence equipment.

In a separate summit with Philippine President Ferdinand Marcos Jr., Biden warned of Beijing's South China Sea moves.

Beijing slams US-Japan-Philippines summit, says S. China Sea actions 'lawful'

US President Joe Biden held a trilateral meeting with Japanese Prime Minister Fumio Kishida and Philippine President Ferdinand Marcos Jr.

Beijing on Friday criticised the United States, Japan and the Philippines and defended its actions in the South China Sea as "lawful" after US President Joe Biden hosted a trilateral meeting in Washington.

Biden on Thursday pledged to defend the Philippines from any attack in the South China Sea at the White House summit, which came amid repeated confrontations between Chinese and Philippine vessels in the disputed waterway that have raised fears of wider conflict.

A joint statement issued by the leaders of the trio of nations voiced "serious concern" over Beijing's actions in the South China Sea, slamming its behaviour as "dangerous and aggressive".

Beijing claims almost the entirety of the South China Sea, brushing aside competing claims from several Southeast Asian nations including the Philippines.

On Friday China hit out at the joint summit in Washington, with foreign ministry spokeswoman Mao Ning saying Beijing "firmly opposes the relevant countries manipulating bloc politics, and firmly opposes any behaviour that provokes or lays plans for opposition, and hurts other countries' strategic security and interests".

"We firmly oppose engaging in closed cliques that exclude others in the region," Mao told a regular press conference.

"Japan and the Philippines can of course develop normal relations with other countries, but they should not invite factional opposition into the region, much less engage in trilateral cooperation at the cost of hurting another country's interests.

"If these are not wanton smears and attacks on China, what are they?" she said.

"China's actions in the East China Sea and South China Sea are appropriate and lawful, and beyond reproach," Mao added.

- 'Ironclad' -

On Thursday Biden told Philippines President Ferdinand Marcos Jr and Japanese Prime Minister Fumio Kishida that the United States' defence commitments to Japan and to the Philippines are "ironclad".

As they met around a horseshoe-shaped wooden table in the grand East Room of the US presidential residence, the US, Japanese and Philippine leaders hailed the meeting as "historic."

Without mentioning China by name, they painted their alliance as a bedrock of peace and democracy in the Asia-Pacific region in contrast to authoritarian Beijing.

Marcos, seen as closer to Washington than his more China-leaning predecessor Rodrigo Duterte, said they shared an "unwavering commitment to the rules-based international order."

Kishida said that "multi-layered cooperation is essential" and that "today's meeting will make history."

Biden, 81, also held separate talks with Marcos, 66, the son and namesake of the country's former dictator.

- 'Purely defensive' -

The joint summit came a day after Biden hosted a lavish state visit for Japan's Kishida during which he unveiled a historic upgrade in defence ties aimed at countering a resurgent China.

Kishida gave a joint address to Congress in which he urged Americans to overcome "self-doubt" about their role as a global power.

This time directly warning of risks from the rise of China, Kishida said that Japan -- stripped of its right to a military after World War II -- was determined to do more to share responsibility with its ally the United States.

The United States, Japan and the Philippines are expected to announce new joint naval exercises along with Australia, similar to drills they had in the region at the weekend, officials said.

They are also set to unveil new economic cooperation measures.

The United States has a mutual defence pact with Manila but there are fears it could be put to the test, with tensions becoming particularly acute around the Second Thomas Shoal, a remote reef in the Spratly Islands.

Japan and the Philippines are the latest Asia-Pacific allies to be hosted by Biden, who was joined by Kishida and South Korean President Yoon Suk Yeol at Camp David in August.

But Biden has also moved to manage tensions with China, holding a two-hour phone call with President Xi Jinping last week following a face-to-face meeting in San Francisco in November.

On Wednesday Biden said the major upgrade in defence ties with Japan was "purely defensive" and "not aimed at any one nation or a threat to the region."

U.S., Japan, Philippines condemn Beijing's South China Sea moves in summit

Long-simmering tensions between China and its neighbors took center stage on Thursday as leaders of the U.S., Japan and the Philippines met at the White House to push back on Beijing's stepped-up pressure on Manila in the disputed South China Sea.

U.S. President Joe Biden's administration announced new joint military efforts and infrastructure spending in the former American colony while he hosted Philippines President Ferdinand Marcos Jr. alongside Japanese Prime Minister Fumio Kishida in Washington for a first-of-its-kind trilateral summit.

Topping the meeting's agenda was China's increasing pressure in the South China Sea, which has escalated despite a personal appeal by Biden to Chinese President Xi Jinping last year.

"We express our serious concerns about the People’s Republic of China’s dangerous and aggressive behavior in the South China Sea. We are also concerned by the militarization of reclaimed features and unlawful maritime claims in the South China Sea," the countries said in a statement issued after the summit.

China's foreign ministry spokesperson Mao Ning said on Friday the statement amounted to a "wanton smear attack" and Beijing summoned a Japanese diplomat to protest against the comments.

The Philippines and China had several maritime run-ins last month that included the use of water cannon and heated verbal exchanges. The disputes center on the Second Thomas Shoal, home to a small number of Filipino troops stationed on a warship that Manila grounded there in 1999 to reinforce its sovereignty claims.

Launching the White House meeting with the three leaders, Biden affirmed that a 1950s era mutual defense treaty binding Washington and Manila would require the U.S. to respond to an armed attack on the Philippines in the South China Sea.

"United States defense commitments to Japan and to the Philippines are iron clad," he said.

Marcos has successfully pushed Washington to resolve longstanding ambiguity over the treaty by specifying that it would apply to disputes in that sea.

China claims almost the entire South China Sea, including the maritime economic zones of neighboring nations. The Second Thomas Shoal is within the Philippines' 200-mile (320-km) exclusive economic zone. A 2016 ruling by the Permanent Court of Arbitration found that China's sweeping claims have no legal basis.

Japan has a dispute with China over islands in the East China Sea.

The three countries said their coast guards planned to conduct a trilateral exercise in the Indo-Pacific region in the coming year and establish a dialogue to enhance future cooperation.

The moves come after two prominent U.S. senators introduced a bipartisan bill on Wednesday to provide Manila with $2.5 billion to boost its defenses against Chinese pressure.

"China's frequent tactic is to try to isolate the target of its pressure campaigns, but the April 11 trilateral signals clearly that the Philippines is not alone," said Daniel Russel, who served as the top U.S. diplomat for East Asia under former President Barack Obama.

The leaders also unveiled a wide range of agreements to enhance economic ties during the meetings, including backing new infrastructure in the Philippines, aimed at ports, rail, clean energy and semiconductor supply chains.

Biden vows to defend Philippines from attack in South China Sea

Joe Biden has said Washington’s commitment to defending its allies in East Asia was “ironclad” as he promised to back Philippines against China’s attacks in the disputed South China Sea.

The US president met Philippine president Ferdinand Marcos Jr and Japanese prime minister Fumio Kishida at the White House on Thursday as tensions and concerns about provocative Chinese military action in the Indo-Pacific continued to surge.

“The United States’ defence commitments to Japan and to the Philippines are ironclad,” the US president said during his first-ever trilateral summit with the leaders from both the Asian nations.

“As I said before, any attack on Philippine aircraft, vessels or armed forces in the South China Sea would invoke our mutual defence treaty,” Mr Biden said.

The naval forces of China and Philippines have had direct confrontation in the South China Sea, especially in the disputed reef of Second Thomas. While Beijing claims direct ownership of the submerged reef, the Philippines has a garrison sitting atop a grounded warship in the waters.

The White House has called the trilateral meeting as a potent response from the US, Japan and the Philippines to China’s repeated “intimidation” attempts. A Biden administration official said that this first-ever meeting will send a message that China is “the outlier in the neighbourhood”.

According to a statement from the White House, Mr Biden and Mr Marcos during the talks “underscored their commitment to international law in the South China Sea” and reaffirmed their countries’ treaty obligations to defend each other.

Japan, Philippines and the US will also hold joint patrols in the Indo-Pacific region this year, a form of a follow-up on law enforcement drills carried out last year by the allies in the waters near the South China Sea.

The US Coast Guard will welcome members from the Philippine and Japanese coast guard onto their vessel during the patrol for training, the White House said.

Mr Biden also announced that the three nations were launching a new economic corridor in the Philippines as part of the G7 Partnership for Global Infrastructure Investment that would help develop clean energy, port, agriculture and other projects in the country.

The US president added that the three leaders were forging a “new era” and predicted “a great deal of history in our world will be written in the Indo-Pacific in the coming years.”

This is a landmark visit for Mr Kishida who also attended a glitzy dinner at the White House on Wednesday after one-on-one talks concluded.

He is the first Japanese leader to visit Washington as a state guest since former prime minister Shinzo Abe in 2015 who revised the interpretation of Japan’s pacifist Constitution to allow its self-defense-only principle to also cover its ally, the US.

In US meeting, Philippines says it will assert South China Sea rights

The Philippines' foreign minister said on Friday his country was determined to assert its sovereign rights in the South China Sea, at a meeting with U.S. allies over an increasingly fraught standoff with Beijing over the waterway.

Enrique Manalo accused China of escalating what he called the harassment of the Philippines and U.S. Defense Secretary Lloyd Austin said Washington stood with Manila against he described as coercion.

An escalating diplomatic row and recent maritime run-ins between China and the Philippines, a U.S. treaty ally, have made the highly strategic South China Sea a potential flashpoint between Washington and Beijing.

The officials spoke at a meeting between U.S. and Philippines defence and foreign secretaries and their national security advisers, a day after the leaders of the U.S., Japan and the Philippines met at the White House over the issue.

"We are determined to assert our sovereign rights, especially within our economic - exclusive economic zone," Manalo said.

He added that he hoped the meeting with U.S. officials would allow Washington and the Philippines to better coordinate their responses on the diplomatic and defence and security fronts to actions in the South China Sea.

Austin said the U.S. commitment to its mutual defence treaty with the Philippines was "ironclad".

"We're working in lockstep with our colleagues at the (Philippines) Department of National Defence to strengthen interoperability between our forces, to expand our operational coordination and to stand up to coercion in the South China Sea," he said.

Earlier on Friday, China summoned Japanese and Philippine diplomats to express dissatisfaction over negative comments about it aired during the White House summit, the foreign ministry in Beijing said.

At summits this week in Washington, the allied leaders unveiling a wide range of pacts to boost security and economic ties.