The UN special envoy for Yemen has warned that the nation is "one step" from famine, as he called for a humanitarian ceasefire during Ramadan as the first step towards a more sustainable truce.
Ismail Ould Cheikh Ahmed said after briefing the UN Security Council that 21 million people were in need of humanitarian assistance compared with seven million two years ago.
The crisis is a result of fighting between Shia Houthi fighters and allied troops loyal to former president Ali Abdullah Saleh against forces loyal to exiled President Abd-Rabbu Mansour Hadi and an allied Arab coalition.
Ould Cheikh Ahmed said that all parties to the conflict were responsible for the suffering of the Yemeni people until there was "a true ceasefire" that could be monitored by "an international, impartial mechanism".
The envoy, who mediated talks between the parties in Geneva last week, said that despite the deep divisions and failure to reach any agreement, "both sides showed signs of constructive engagement and there is an emerging common ground upon which we can build to achieve an eventual ceasefire coupled with the withdrawal of combatants".
The humanitarian crisis in the Arab world's poorest country has escalated as the conflict has intensified, leaving 20 million Yemenis without access to safe drinking water and uprooting another one million people from their homes.
Al Jazeera's correspondent Omar al-Saleh described the situation in the capital Sanaa as "dire".
"There are long queues for almost everything here. There is no running water and many rely on tankers. It's often hours before one arrives," Saleh said.
A near-blockade of Yemen's ports has also made it difficult to deliver humanitarian aid, although the International Committee of the Red Cross said a ship carrying 1,000 tonnes of food and three large generators from Oman docked in Yemen's Hodeida port on Wednesday.
Saudi soldiers and UAE officer killed
Meanwhile, as fighting continued across Yemen on Thursday, Saudi state media reported that shelling by the Houthi fighters killed four soldiers from Saudi Arabia and the United Arab Emirates stationed on Yemen's border with the kingdom.
The Houthis have stepped up attacks on Saudi border posts in recent weeks, despite three months of bombardment by an Arab-led coalition intent on restoring Yemen's government in exile.
Two soldiers from the Royal Saudi Land Forces, one from the kingdom's Border Guards, and a UAE officer were killed on Wednesday in three incidents along the border, a mostly mountainous area.
The Houthis and their allies in Yemen's army have managed to hold most of the populated western part of the country against forces in Aden, Taiz, Dhalea, and Marib which are backed by coalition air strikes.
Bombings in the Houthi-controlled capital of Sanaa also continued on Thursday, as a remote-controlled bomb detonated outside the state news agency, killing a Houthi fighter and wounding two others, residents said.
Saudi Arabia's coalition of Arab countries wants to force the Houthis to quit captured areas, return seized arms and let President Hadi return from his Riyadh exile in line with a UN Security Council resolution.
However, neither side appears ready to make concessions, causing the collapse of last week's UN-sponsored talks.
Source: Al Jazeera and agencies