"China calls on all parties to the conflict, especially Israel, to cease fire as soon as possible," the ministry said in a statement.

Hours earlier President Donald Trump said US warplanes struck three Iranian nuclear sites, as Washington joined Israel's war with Tehran in a flashpoint moment for the Middle East.

Iran's foreign minister said Sunday the United States and Israel had "crossed a very big red line" and that Iran would defend itself "by all means necessary".

Beijing's foreign ministry joined Russia and a chorus of Arab states in condemning the US air strikes.

Chinese President Xi Jinping said last week a ceasefire between Iran and Israel was the "top priority" during a phone call with Russia's Vladimir Putin.

"Armed force is not the correct way to resolve international disputes," Xi said, quoted by Beijing's foreign ministry.