The report, which cited information from two unidentified senior officials in US President Donald Trump's administration, said contract chipmaker SMIC "began sending the tools to Iran roughly a year ago".

A US official was quoted in the report as saying they had "no reason to believe that any of this has stopped".

China is a key partner of Iran but has not announced military assistance to Tehran in the war triggered by US-Israeli strikes on February 28, repeatedly calling for a ceasefire.

The chipmaker, Semiconductor Manufacturing International Corporation (SMIC), did not respond to an AFP request for comment on Friday.

Asked about the report at a regular news conference in Beijing, foreign ministry spokesman Lin Jian said he was "not familiar with the situation".

"What I can tell you is that recently, some media have been keen on releasing some news that seems right but instead is wrong," Lin said.

He added that, "after verification", such reports were "all" found to be "false information" but did not elaborate.

China condemned the US-Israeli killing of Iranian supreme leader Ali Khameini but has also said it "does not go along" with Tehran's strikes on Gulf states hosting US bases.

Beijing's top diplomat Wang Yi told his Iranian counterpart Abbas Araghchi in a phone call this week that he hoped "all parties can seize every opportunity and window for peace and start the peace talks process".