The rebel-run Saba news agency said women and children were among at least 31 people killed or wounded in an air strike that hit a bus and a home in the Al-Durayhimi district, south of the strategic port city of Hodeida.

But the United Arab Emirates, a key partner in the Saudi-led coalition, said the Huthis launched a "ballistic (missile) made in Iran".

A child was killed and dozens of others were wounded, three of them seriously, according to Emirati state news agency WAM.

It was not immediately possible to independently verify the accounts given by the two sides.

The Al-Durayhimi area lies some 20 kilometres (12 miles) south of Hodeida, and has seen two weeks of fighting between the rebels and pro-government forces backed by the UAE.

But the wider offensive to retake Hodeida from the Huthis has been halted pending the outcome of negotiations, the coalition has said.

The latest civilians deaths comes after 40 children and 11 adults were killed in an attack in northern Yemen earlier this month.

The August 9 air strike sparked international condemnation and the Saudi-led coalition announced an investigation.

The coalition has been accused of causing numerous civilian casualties in the civil war in Yemen.

It has admitted a small number of mistakes, but accuses the Huthis of routinely using civilians as human shields.

A report published by Human Rights Watch on Friday said the coalition's investigations into alleged war crimes "have lacked credibility".

"For more than two years, the coalition has claimed that (its investigative body) JIAT was credibly investigating allegedly unlawful air strikes, but the investigators were doing little more than covering up war crimes," HRW's Middle East director, Sarah Leah Whitson, said in a statement.

The coalition led by Saudi Arabia intervened in support of President Abedrabbo Mansour Hadi as he fled into exile in the face of a rebel offensive in 2015.

It has recaptured most of the south and stretches of the Red Sea coast but the capital Sanaa and much of the north remain in the hands of the rebels.

The conflict has killed nearly 10,000 people and triggered what the United Nations has described as the world's worst humanitarian crisis.