Twenty-two civilians, including children, were killed in air raids earlier this week in Daleh and Amran provinces, the United Nations said.

The strikes came after the Iran-backed Huthis offered to halt drone and ballistic missile attacks on Saudi Arabia as part of efforts to end a war that has pushed Yemen to the brink of famine.

"The initiative is still on, and we are patient," Hisham Sharaf, the Huthis' foreign minister, told AFP.

"If they want peace, we are for peace. If they don't want peace, they know how we can hit them hard."

The rebels have claimed responsibility for the September 14 attacks on Saudi oil installations that knocked out half of the OPEC kingpin's production and sent shock waves through world energy markets.

The United States and Saudi Arabia however blamed Iran, saying the strikes were carried out with advanced cruise missiles and drones.

According to the UN, seven civilians including women and children from the same family were killed when air strikes hit a mosque on Monday in the rebel-held northern province of Amran.

The next day 15 people including seven children were killed in raids on southern Daleh province, partly controlled by the insurgents.

The strikes marked the first major attack believed to have been carried out by the coalition since the Huthis' offer.

Sharaf said the Huthis will give the Saudi-led coalition more time.

"We find that they're trying to distract the whole world from our initiative by launching these air strikes," he said.

"We will give them time even if they're killing our people."

Tens of thousands of people, most of them civilians, have been killed since Saudi Arabia and its allies intervened in March 2015 in support of the internationally recognised government after the rebels captured the capital Sanaa.

The fighting has displaced millions and left 24.1 million -- more than two-thirds of the population -- in need of aid.

The United Nations has described Yemen as the world's worst humanitarian crisis.