UN mediator Hans Grundberg will also push for the release of UN staff and others currently being held there.

The United Nations' Yemen mediator arrived in Yemen's capital on Monday as part of a bid to subdue heightened tensions in his first visit in almost two years, a spokesperson said.

The trip comes amid intensified Israeli and US strikes on Houthi strongholds in the past two weeks in response to the Iran-backed militants launching missiles and drones towards Israel. The strikes disrupted operations at Sanaa International Airport, Hodeidah and Saleef ports, which are the main aid entries.

The Iran-aligned Houthis have controlled most parts of Yemen, including the capital Sanaa, since seizing power during 2014 and early 2015. They are playing an escalating role in the Middle East in a campaign aimed at supporting Palestinians in the Gaza war.