China said its top diplomat discussed tensions in the Middle East on a call with Secretary of State Antony Blinken, underscoring fears that the six-month-old Gaza conflict may escalate.

Wang Yi “stressed that China strongly condemns the attack on the Iranian embassy in Syria,” Foreign Ministry spokeswoman Mao Ning said at a regular press briefing in Beijing.

China called on all parties to the crisis in Gaza to “immediately stop the fighting and prevent a humanitarian crisis,” Mao said on Friday. She added that “the US in particular needs to play a constructive role.”

Read More: US Sees Imminent Missile Strike on Israel by Iran, Proxies

Iran has threatened to hit Israel in retaliation for an attack on a diplomatic compound in the Syrian capital of Damascus last week. Israel hasn’t explicitly acknowledged it was behind that attack.

China maintains close ties with Iran, helping broker a detente between Tehran and Riyadh a year ago. Most Iranian oil exports go to China.

Read More: Biden Vows to Back Japan, Philippines as China Jolts Allies

Mao avoided a question about whether Wang and Blinken discussed the South China Sea. China and the Philippines have been involved in a series of tense encounters near a disputed shoal there, and recently the US, Japan, Australia and the Philippines patrolled the waters.

On Thursday, President Joe Biden said that “any attack on Philippine aircraft, vessels or armed forces in the South China Sea would invoke our mutual defense treaty.”