Saudi-led truce in Yemen expires amid fears of coronavirus disaster

* Fighting escalates after ceasefire announcement

* Diplomats see ceasefire as symbolic

* Houthi group says lifting blockades a condition

* The movement threatens central Marib city

By Aziz El Yaakoubi

DUBAI, April 23 (Reuters) - A two-week ceasefire in Yemen announced by a Saudi-led military coalition expired on Thursday without leading to a permanent truce, raising fears that the country's war will grind on and shatter its already weakened ability to combat coronavirus.

The latest Yemen peace push follows U.N. Secretary-General Antonio Guterres's call last month for a global ceasefire so the world can focus on fighting COVID-19, which aids groups worry could cause a catastrophe in Yemen after five years of war.

But the Iran-aligned Houthi group battling the coalition did not accept the coalition's ceasefire announcement, and violence has continued in several provinces including Marib, the last stronghold of the Saudi-backed government.

Two diplomats and two other sources familiar with the matter had expected an extension of the ceasefire for at least another two weeks, if not until the end of the holy fasting month of Ramadan, expected to begin this week.

But since the Houthis continued their attacks, the coalition did not extend it, they said. The Western-backed alliance has responded to recent Houthi advances with air strikes.

"It was rather a symbolic ceasefire than an actual one, the coalition does not see the point of extending it," one of the sources close to the discussions told Reuters.

A spokesman of the Saudi-led coalition did not respond to a Reuters' request for comment.

"The Houthis could conduct an assault on Marib city very soon if there is no agreement, this would be another disastrous episode in the ground war after the battles for (the Red Sea port of) Hodeidah in 2018," said a Saudi-based Western diplomat.

The Saudi-backed government was ousted from power in the capital, Sanaa, in late 2014 by the Houthi movement, which now holds most big urban centres.

During the past two weeks, the United Nations has sought to hold virtual talks among the parties to cement a truce, coordinate a coronavirus response and agree confidence-building measures to restart peace talks.

The pressing need is to end a ruinous war that has left millions vulnerable to disease. While Yemen has reported only one laboratory-confirmed case of the novel coronavirus, aid organisations fear a "catastrophic" outbreak should the virus spread among an acutely malnourished population, due to the country's inadequate testing capabilities.

"NOT ROCKET SCIENCE"

Yemen has been mired in conflict since the Sunni Muslim coalition intervened in March 2015 to try to restore the Saudi-backed government to power. The costly and unpopular war has been in stalemate for years and Saudi Arabia's key coalition partner largely reduced its presence last year, leaving Riyadh to lead the military campaign.

Saudi Arabia resumed indirect talks with the Houthis, first launched late last year, to try to make the ceasefire binding on both sides. But the group wants to see air and sea blockades lifted first, sources close to the talks had told Reuters.

The coalition says it patrols Yemen's coast and controls the airspace to prevent arms smuggling.

The conflict, which has killed more than 100,000 and pushed the country to the verge of famine, is widely seen in the region as a proxy war between Saudi Arabia and Iran. The Houthis say they are fighting a corrupt system.

Special U.N. envoy Martin Griffiths told the U.N. Security Council on Thursday he expects the combatants to formally adopt "in the immediate future" agreements on a nationwide ceasefire, economic and humanitarian measures and a resumption of political talks.

However, the Houthis' spokesman Mohammed Abdusalam said U.N. proposals ignore important issues including the blockade and use "jargon which does not allow any commitment".

"Ceasefires anywhere in the world depend on joint mechanisms, this is not rocket science, this is not unique to Yemen, we are not re-inventing any wheels here," Griffiths told Saudi-owned television channel Al Arabiya on Wednesday. (Reporting by Aziz El Yaakoubi, Editing by William Maclean)