US and Israeli attacks on Iran are unacceptable, China's Foreign Minister Wang Yi said on Sunday as he called for an immediate ceasefire and the resumption of talks to prevent a wider regional conflict.

The “blatant killing of a sovereign leader” and the incitement of regime change were “unacceptable,” Wang told Russia’s Foreign Minister Sergei Lavrov on a phone call, according to China’s state-run Xinhua news agency.

The US and Israel attacked Iran early on Saturday, killing Iran’s Supreme Leader Ali Khamenei. US President Donald Trump urged Iranians to seize the moment and “take over” the government.

Wang said China wanted an immediate cessation of military action and a return to dialogue as soon as possible.

On Sunday, China’s embassy in Israel advised its nationals to evacuate to safer areas within the country or to leave for Egypt via the Taba border crossing.

China’s foreign ministry on Sunday also urged Chinese citizens in Iran to leave “as soon as possible”, listing four land routes to Azerbaijan, Armenia, Turkey and Iraq.

Iran has launched retaliatory strikes with the aim of hitting US bases in the region, but other places in Gulf cities have also been hit.

Chinese citizens have been injured in the attacks, and some of them have been stranded, China’s foreign ministry said, warning Chinese nationals against travelling to the region altogether.

In a commentary on Sunday, China’s state-run Xinhua news agency criticised the attack, calling it “brazen aggression against a sovereign nation” and “power politics and hegemony”.

Xinhua said Washington's use of military coercion was a “flagrant violation” of the purposes and principles of the United Nations Charter and a departure from “fundamental norms of international relations”.

The conflict has caused widespread flight disruptions and cancellations.

Hong Kong-based airline operator Cathay Group on Saturday suspended operations in the Middle East, affecting passenger flights to and from Dubai and Riyadh as well as freighter services through Al Maktoum International Airport in Dubai, Cathay, the parent of Cathay Pacific Airways said in a statement.

It said it was re-routing flights that typically pass over the affected area.