An air strike by a Saudi-led military coalition killed 21 people at a market in Yemen's northern Saadah province on Wednesday, the Houthi rebel group said Wednesnday.

The attack which struck the Sahar district of the vast territory, on the border with Saudi Arabia, reduced the site to a heap of twisted sheet metal. Medics gathered corpses and laid them in a group.

The Houthi-run Saba news agency, citing a security source, said the raid targeted a small hotel in a marketplace in Sahar in the province. Saada is a main stronghold of the Shia Houthi group in Yemen. The agency said 9 people were seriously injured in the attack, without giving further details.

There was no comment from the Saudi-led coalition on the Houthi claim.

A military alliance led by Saudi Arabia has launched thousands of air strikes against Yemen's armed Houthi movement, which hails from Saadah and now controls much of the country.

The 2-1/2 year war effort has yet to achieve its goal of restoring to power the internationally recognised government, but the conflict has unleashed one of the world's worst humanitarian crises and killed at least 10,000 people.