ADEN (Reuters) - The U.N. Yemen mediator is in talks with the Houthi movement to hand over control of Hodeidah port to the United Nations in an attempt to avert a possible assault on the city by a Saudi-led coalition, Yemeni political sources said.

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Martin Griffiths arrived in the Houthi-held capital Sanaa on Saturday as coalition-backed troops moved to within 10 km (6.21 miles) of the Red Sea port, long a key target in the war, according to local military officials, who said the advance had paused in the last few days.

“He (Griffiths) comes with a proposal for the Houthis to place Hodeidah port under U.N. supervision,” said a senior Yemeni politician close to the internationally recognized government of President Abd-Rabbu Mansour Hadi, who is in exile.

A source close to the Iran-aligned Houthi movement confirmed that the proposal was being discussed as did a second source close to Hadi’s government.

A spokesperson for the Saudi-led coalition did not immediately respond to a Reuters request for comment.

The renewed thrust towards Hodeidah coincides with increased tensions between Saudi Arabia and Iran, which are locked in a three-year-old proxy war in Yemen that has killed more than 10,000 people, displaced three million and pushed the impoverished country to the verge of starvation.

International aid agencies have warned that a major battle for Hodeidah, with a 400,000 population, could lead to a bloodbath and shut down a port that handles most of Yemen’s commercial imports and critically-needed aid supplies.

Mark Lowcock, U.N. emergency relief coordinator, said on Monday that the United Nations was in touch with several U.N. member states about Hodeidah.

He said Griffiths was due to brief the Security Council on June 18. “And obviously the situation in Hodeidah is one of the things that he’s looking at,” he added.

The Yemeni sources said Griffiths met several Houthi officials, including the group’s foreign minister, but had yet to meet Mahdi al-Mashat, who holds the post of president in the Houthi-backed political body which runs most of north Yemen.

The Western-back alliance of mostly Gulf Arab states, which intervened in Yemen’s war in 2015 to restore Hadi’s government, last year announced plans to move on Hodeidah, but backed off amid international pressure.

It was unclear if Saudi Arabia’s Western allies, which have come under increasing scrutiny for arms sales to coalition member states, have approved an attack on Hodeidah.

Troops backed by the United Arab Emirates (UAE), a part of the coalition, have made gains along the southwestern coast of Yemen as part of a strategy to box the Houthis in around Sanaa.

Gulf government officials familiar with UAE and Saudi thinking have said capturing the coast would block Houthi supply lines and push the group to the negotiating table.

Riyadh says the Houthis use Hodeidah to smuggle Iranian-made arms into Yemen, accusations denied by the group and Tehran.

The United Nations has beefed up its inspections of ships bringing humanitarian aid to ensure that no military items are being smuggled and to speed delivery of desperately-needed relief supplies.