Iran was "deeply involved" in planning operations against commercial vessels in the Red Sea and its intelligence was critical to enable Yemen's Houthi movement to target ships, the White House said on Friday.

Iran-backed Houthis, who say their attacks are in support of Palestinians under siege by Israel in Gaza, have targeted commercial shipping in the Red Sea with drones and missiles, forcing shippers to change course and take longer routes around the southern tip of Africa

"We know that Iran was deeply involved in planning the operations against commercial vessels in the Red Sea. This is consistent with Iran's long-term materiel support and encouragement of the Houthis' destabilizing actions in the region," White House national security spokeswoman Adrienne Watson said in a statement.

"This is an international challenge that demands collective action," Watson said.

Iran denies involvement in attacks by the Houthis in the Red Sea.

The U.S. last week announced a naval coalition involving 20 countries aimed at helping safeguard vessels from attacks in the Red Sea. Some of the countries involved have said operations to protect commercial traffic will be as part of existing naval agreements.

Iranian Spy Vessel Directs Houthi Rebel Attacks in Red Sea.

Iran is supplying Houthi rebels in Yemen with military intelligence and weapons such as ballistic missiles and drones to strike commercial ships in the Red Sea, The Wall Street Journal reported on Friday, crediting Western and regional security representatives. United States National Security Council spokesperson Adrienne Watson also confirmed the findings to CNN. CNN previously found that the Houthis have perpetrated over 100 attacks on roughly a dozen merchant vessels over the past month. The Iranian mission to the United Nations did not respond to a request for comment from WSJ. In response, Secretary of Defense Lloyd Austin announced the establishment of Operation Prosperity Guardian on Monday “with the goal of ensuring freedom of navigation for all countries and bolstering regional security and prosperity.” Air Force Major General and Pentagon Press Secretary Pat Ryder said in a Thursday press conference that more than 20 nations have signed on. The Houthi rebels’ attacks on ships they blame for supporting Israel’s war on Hamas have skyrocketed since Oct. 7, and companies like BP have stopped shipments through the Red Sea as a result. Mohammed al-Bukhaiti, a senior Houthi official, told Al Jazeera on Monday that they would fight the U.S. and any other countries who challenged them.

White House accuses Iran of being "deeply involved" in Red Sea attacks

The U.S. on Friday accused Iran of close involvement in attacks on commercial ships by Yemen's Houthi rebels, stepping up the tone as Washington considers tougher measures including possible force.

The White House publicly released U.S. intelligence as the Iranian-linked Yemeni insurgents persist with ship strikes they say are in solidarity with Palestinians in the Gaza Strip, where Israel is battling Hamas militants.

The White House said that Tehran's clerical state has provided drones and missiles to the Houthis as well as tactical intelligence.

"We know that Iran was deeply involved in planning the operations against commercial vessels in the Red Sea," National Security Council spokeswoman Adrienne Watson said.

"We have no reason to believe that Iran is trying to dissuade the Houthis from this reckless behavior," she said.

The Houthis, who control vast parts of the Arabian Peninsula's poorest country, including the capital Sanaa, have launched more than 100 drone and missile attacks, targeting 10 merchant vessels, according to the Pentagon.

On Tuesday, Defense Secretary Lloyd Austin held an emergency meeting with defense officials from dozens of countries, along with the European Union and NATO, to address what he called "reckless, dangerous" attacks which "violate international law."

Last week, U.S. Central Command reported that the USS Carney, a guided missile destroyer, shot down 14 attack drones suspected to have been fired from Houthi-controlled regions of Yemen.

In a Nov. 15 interview with CBS News, Iranian Foreign Minister Hossein Amir-Abdollahian denied that Iran was responsible for a drone fired from Yemen that was shot down by the guided-missile destroyer USS Thomas Hudner. The drone appeared to be targeting the Hudner, U.S. officials said at the time.

"We really didn't want this crisis to expand," Amir-Abdollahian told CBS News, referencing the Israel-Hamas war. "But the U.S. has been intensifying the war in Gaza by throwing its support behind Israel. Yemen makes its own decisions and acts independently."

Earlier this week, energy giant BP announced it was temporarily suspending all gas and oil shipments in the Red Sea because of the attacks.

And with commercial traffic disrupted, the U.S. recently announced a multinational naval task force of more than 20 countries to protect vessels transiting the Red Sea.

In a show of force, the aircraft carrier USS Dwight D. Eisenhower has entered the Gulf of Aden.

Rebel leader Abdel-Malek al-Houthi warned Wednesday that if they were attacked, the rebels would strike back against "American battleships, American interests and American navigation."

The White House said that U.S. visual analysis found nearly identical features between Iran's KAS-04 drones and the unmanned vehicles fired by the Houthis, as well as consistent features between Iranian and Houthi missiles.

The Houthis are also reliant on Iranian-provided monitoring systems at sea, the White House said.

"Moreover, Iranian-provided tactical intelligence has been critical in enabling Houthi targeting of maritime vessels since the group commenced attacks in November," Watson said.

The Biden administration had initially kept a low-key tone on the Houthi attacks, in part out of an interest in preserving a fragile peace in Yemen.

The Houthis and the Saudi-backed government have effectively maintained a United Nations-brokered truce since April 2022, halting a devastating war that triggered a humanitarian crisis in which most of the population relies on aid.

Iran's religious leadership openly supports Hamas, whose gunmen broke through Gaza's militarized border on Oct. 7 and killed more than 1,200 people in Israel, mostly civilians, and abducted several hundred more.

U.S. officials have said they have no evidence that Tehran had previous knowledge or directly planned the attack.

Israel has vowed to destroy Hamas. Its relentless bombardment and ground invasion of Gaza has killed more than 20,000 people, most of them women and children, according to Hamas authorities.