* U.N. to hold video conference with both sides on Hodeidah deal
* Truce was first breakthrough in peace efforts in years
* Hodeidah is a lifeline for millions facing starvation
* Western nations are pressing for an end to the war
By Mohammed Ghobari
ADEN, Dec 19 (Reuters) - Yemen's warring parties have traded accusations of breaching a ceasefire in Hodeidah that was mediated by the United Nations to avert a full-scale assault on a port city vital for food and aid supplies, and pave the way for peace negotiations.
Residents reported shelling late on Tuesday, the first day of the truce, for nearly one hour on the eastern and southern outskirts of the Houthi-held Red Sea city, a lifeline for millions. It was calm early on Wednesday.
The United Nations is due to convene the Iran-aligned Houthi group and the Saudi-back government by video link on Wednesday to discuss a troop withdrawal from Hodeidah city and three ports under the truce deal agreed at U.N.-led talks in Sweden last week, the first in more than two years.
Houthi-run al-Masirah TV accused Saudi-led coalition forces of breaching the truce by shelling several sites, including areas east of the airport. The United Arab Emirates news agency WAM quoted a Yemeni source as saying the Houthis fired mortar bombs and rockets at the May 22 hospital in the eastern suburbs.
"We will continue to give them (Houthis) the benefit of the doubt and show restraint, but early indicators are not promising," a coalition source told Reuters.
"If the UN ... takes too long to get into (the) theatre, they will lose the opportunity altogether and the Stockholm agreement will turn to a dead duck," said the source, who declined to be named.
Under the ceasefire deal, international monitors would be deployed and all armed forces would pull out within 21 days of the truce.
Hodeidah, the main port used to feed Yemen's 30 million people, has been the focus of fighting this year, raising global fears that a full-scale assault could cut off supplies to 15.9 million people facing severe hunger.
Western nations have pressed the Sunni Muslim Arab coalition led by Saudi Arabia and the UAE to end the nearly four-year war that has killed tens of thousands of people.
The alliance, which receives arms and intelligence from the West, intervened in the war in 2015 to restore the government of Abd-Rabbu Mansour Hadi that was ousted from the capital, Sanaa, in 2014 by the Houthis, who control most towns and cities.
Coalition-backed Yemeni forces have massed on the outskirts of Hodeidah to try to seize the port and weaken the Houthi group by cutting off its main supply line.
The truce, the first significant breakthrough in peace efforts in five years, was part of confidence-building steps to pave the way for a wider truce in the impoverished Arabian Peninsula country and a framework for political negotiations.
The U.N. video conference will be the first meeting of the Redeployment Coordination Committee overseeing the ceasefire and withdrawal. It includes three representatives from both sides.
The committee will be chaired by retired Dutch Major General Patrick Cammaert who is expected leave New York later this week to travel to Yemen.
The U.N. Security Council is considering a resolution to ask U.N. chief Antonio Guterres to submit proposals by the end of the month on how to monitor the truce and forces redeployment. (Additional reporting and writing by Ghaida Ghantous; Editing by Alison Williams, Robert Birsel and Hugh Lawson)
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