Wang also stressed that the UN Security Council (UNSC) -- of which China is a permanent member -- "should prevent the escalation of conflict, and not legalise unauthorized military actions", state broadcaster CCTV said, as the international body debates a draft resolution on the use of force in the Hormuz strait.

The resolution introduced by Bahrain would authorise states to use "all necessary means" to ensure freedom of navigation in the Strait of Hormuz, which has been virtually paralysed by Iran since US-Israeli military strikes began late February.

"The military attack launched by the United States and Israel against Iran was not authorised by the UNSC and clearly violated international law", Wang told Germany's foreign minister Johann Wadephul in a phone call Thursday, CCTV reported.

"The actions of the UNSC should focus on easing the situation, not on giving unauthorised military actions the appearance of legitimacy, and certainly not on further intensifying conflict," Wang said in a separate call with the European Union's foreign affairs representative Kaja Kallas.

Beijing is a close partner of Tehran and the main buyer of Iranian oil, most of which passes through the strait.

But it also has strong economic ties to the Gulf countries and has repeatedly criticised attacks on them.

In another call with his Saudi Arabian counterpart, Wang warned "small and medium-sized countries" would bear the brunt of "endless troubles" if the UNSC didn't fulfill its role to deescalate, according to CCTV.

China, together with Pakistan, has put forward a five-point initiative to end the war.