The United Nations Special Envoy for Yemen, Martin Griffiths, expressed sadness on Wednesday at the death of dozens of civilians including children in the airstrikes over the past two days.

"This is yet another heartbreaking event," Griffiths said in a statement.

He called on all parties "to take tangible and quick steps to reduce the violence, respect international humanitarian law and allow for a conducive environment for Yemen to return to a political process without delay."

"Yemen needs to break from this vicious cycle of violence now and be safeguarded from the recent tensions in the region that could risk its prospects for peace," Griffiths added.

The UN Office for the Coordination of Humanitarian Affairs in Yemen (OCHA) said "22 civilians, including women and children, have been killed in two separate airstrikes in the past two days... in the governorates of Amran and Dhalea."

"We share our deepest condolences with the families of the killed and injured," said Lise Grande, humanitarian coordinator in Yemen.

Griffiths has been shuttling between Sanaa and Riyadh to try to rescue a peace deal reached in Sweden last year between the Houthis and the Saudi-backed exiled government.

Saudi Arabia has been leading an Arab military coalition against Iran-allied Houthi rebels in Yemen for more than four years in support of the exiled internationally-recognized government of Yemeni President Abd-Rabbu Mansour Hadi.AFP