As the ruling forces clashed with the Houthi rebels in Yemen's Marib, 65 Houthi soldiers got killed in the ruling government's last stronghold in the oil-rich Northern Province.

The Saudi-led forces led the airstrike in support of the ruling forces which killed and injured dozens of rebels.

A "government" military official told AFP that 22 pro-government soldiers were killed and 50 others were injured in the clashes, and 43 Huthi rebels were killed in the last 48 hours. This figure has been confirmed by other military and medical sources.

Fighting resumed after at least 30 pro-government fighters were killed on Sunday in the deadliest incident since December in an attack on Yemen's largest airbase in the south of the country.

The clashes took place just days before the new UN special envoy to Yemen, Swedish diplomat Hans Grundberg, fulfilled his responsibilities.

The United Nations has declared the region to be facing one of the deadliest humanitarian crises.