Shelling by Yemen's Houthi militia killed four soldiers from Saudi Arabia and the UAE stationed on Yemen's border wth the kingdom, Saudi state media reported early on Thursday.

The Houthis have stepped up attacks on the kingdom's border posts in recent weeks, despite three months of bombardment by a Saudi-led coalition intent on restoring Yemen's exiled government.

Two soldiers from the Royal Saudi Land Forces, one from the kingdom's Border Guards, and an officer from the UAE's forces were killed on Wednesday in three incidents along different stretches of the border, a mostly mountainous area.

The Houthis and their allies, army forces loyal to former president Ali Abdullah Saleh, have managed to hold most of the populated western part of Yemen against disparate groups in Aden, Taiz, al-Dhala and Marib baked by coalition air strikes.

Saudi Arabia's coalition of Arab countries wants to force the Houthis and Saleh to quit captured areas, return seized arms and let President Abd-Rabbu Mansour Hadi return from his Riyadh exile in line with U.N. Security Council resolution 2216.

However, neither side appears ready to make concessions, causing the collapse of U.N. sponsored talks last week. Aid groups say Yemen's humanitarian crisis is worsening as a result of fighting and a coalition embargo.

Saudi Arabia believes the Houthis are closely tied to the kingdom's main regional foe, Iran, though diplomats in the region say those ties may be exaggerated.-Reuters