GENEVA - As forces of the Saudi-led military coalition close in on the main Yemeni port city of Hodeidah, aid agencies fear a major battle that will also shut down a vital lifeline for millions of hungry civilians.Senior aid officials urged Western powers providing arms and intelligence to the coalition to push the mostly Sunni Muslim Gulf Arab allies to reconvene UN talks with the Iran-allied Houthi movement to avoid a bloodbath and end the three-year war.A coalition spokesman said on Tuesday that forces backed by the coalition were 20 kms (12 miles) from the Houthi-held city of Hodeidah, but did not specify whether there were plans for an assault to seize the Red Sea port, long a key target."The coalition ground forces are now at the doorstep of this heavily-fortified, heavily-mined port city," Jan Egeland, secretary-general of the Norwegian Refugee Council, told Reuters. "Thousands of civilians are fleeing from the outskirts of Hodeidah which is now a battle zone.""We cannot have war in Hodeidah, it would be like war in Rotterdam or Antwerp, these are comparable cities in Europe."Troops from the United Arab Emirates and Yemeni government are believed to lead coalition forces massing south of the city of 400,000, another aid official said, declining to be named.Last week UN Aid Chief Mark Lowcock urged the Saudi-led coalition that controls Yemen's ports to expedite food and fuel imports. He warned that a further 10 million Yemenis could face starvation by year-end in addition to 8.4 million already severely short of food in the world's worst humanitarian crisis.