Chinese officials have asked their Iranian counterparts to help rein in attacks on ships in the Red Sea by the Iran-backed Houthis, or risk harming business relations with Beijing, four Iranian sources and a diplomat familiar with the matter said.

The discussions about the attacks and trade between China and Iran took place at several recent meetings in Beijing and Tehran, the Iranian sources said, declining to provide details about when they took place or who attended.

"Basically, China says: 'If our interests are harmed in any way, it will impact our business with Tehran. So tell the Houthis to show restraint,'" said one Iranian official briefed on the talks, who spoke on condition of anonymity.