Two of the vessels passed through the strait, crucial for transporting oil and gas, on Monday as they exited the Gulf, tracking data showed.

The CSCL Indian Ocean crossed the strait at around 0914 GMT on Monday, followed by the CSCL Arctic Ocean 27 minutes later, according to data from MarineTraffic.

"Following coordination with relevant parties, three Chinese vessels recently transited the Strait of Hormuz; we express our gratitude to the relevant parties for the assistance provided," foreign ministry spokeswoman Mao Ning told a regular press conference.

She did not mention Iran or provide details about the third ship.

Shipping through the strait has slowed to a trickle since Iran effectively blocked access following US-Israeli attacks on the country.

The CSCL Indian Ocean and the CSCL Arctic Ocean are both ultra-large container vessels belonging to the Chinese state-owned shipping giant Cosco, which refused to comment on the transits when contacted by AFP.

They passed close to the Iranian-controlled island of Larak and are bound for Port Klang in Malaysia.

The ships had aborted an attempt to transit on Friday, according to MarineTraffic.

Iran has said the Strait of Hormuz is open to ships of "friendly countries". It maintains healthy diplomatic ties with China.

Cosco said on Wednesday it was resuming bookings for shipments from Asia to several Gulf countries, though without using routes that transit Hormuz.

The Shanghai-based firm had suspended bookings for services through the strait earlier in March due to the war.