More than 50 killed in two days of Yemen violence

Seventeen other rebels were wounded in the airstrikes that hit five Houthi-controlled towns controlled around 70 kilometres (45 miles) south of Hodeida, the security sources said.

Yemeni government forces recaptured Beihan district in Shabwa province, their last stronghold in the oil-rich southern province, a senior officer said on Friday.

The capture of Beihan came during clashes that killed 14 rebels and nine pro-government troops, the officer said.

There has been no let-up in the air campaign against the rebels that a Saudi-led coalition has been waging since March 2015.

The airstrikes have intensified since the December 4 killing of former president Ali Abdullah Saleh at the hands of the Houthis after his alliance with the rebels collapsed.

At the same time, forces of the Saudi-backed Yemeni government have stepped up attacks on the rebels and last week recaptured the Red Sea town of Khokha from the Houthis.

New clashes broke out on Friday as government forces tried to push towards Hodeida, the security sources said.

The UN refugee agency UNHCR said it was "bracing for further displacement and a spike in humanitarian needs as hostilities intensify in frontline areas on Yemen's west coast".

Hodeida is the main conduit for UN-supervised deliveries of food and medicine, but the port is controlled by the Houthis and remains closed, forcing the UN to divert aid supplies to other areas.

"To date we have deployed emergency relief items for 2,000 families in Hodeida, and a further 2,000 aid kits are on their way along with 2,000 emergency shelter kits," the UNHCR said in a statement.

"As the port of Hodeida remains closed an additional 43 containers with emergency, shelter and household aid, including plastic tarpaulins and blankets for more than 20,000 families, had to be diverted to Aden," it added.

More than 10,000 people have died since the Saudi-led coalition launched its war on the rebels in March 2015.