Yemen's Iran-aligned Houthis have indicated they would be willing to hand over management of Hodeidah port to the United Nations, a potential breakthrough in a conflict that has caused the world's worst humanitarian crisis, sources familiar with the efforts said. Saudi Arabia and the United Arab Emirates have pledged a swift military operation to take over the airport and seaport without entering the city center, to minimize civilian casualties and maintain the flow of essential goods. The Saudis and Emiratis, who intervened in Yemen in 2015, say they must recapture Hodeidah to deprive the Houthis of their main source of income and prevent them from bringing in missiles. Hodeidah port is a principal entry point for relief supplies for Yemen. U.N. officials have warned that large-scale fighting in the city could threaten tens of thousands. U.N. envoy Martin Griffiths has been in the Houthi-controlled Yemeni capital, Sanaa, and Jeddah, Saudi Arabia, this week to try to negotiate a solution. Deputy U.S. Secretary of State John Sullivan and the head of the U.S. Agency for International Development, Mark Green, met on Thursday with international and non-governmental agencies to discuss the port conflict, the State Department said. At the meeting, Sullivan endorsed "Griffiths' efforts to avoid an escalation in fighting by brokering a compromise over the management of the port" and underscored the U.S. commitment to a political solution, the department said in a statement. A U.S. official said the United States was urging the Saudis and Emiratis to accept the deal. A diplomatic source at the United Nations said the coalition had informed Griffiths it would study the proposal. The source said the Houthis indicated they would accept overall U.N. rule for port management and inspections. A Western diplomat said the United Nations would oversee income from the port and make sure it gets to Yemen's central bank. The understanding is for Yemeni state employees to remain working alongside the United Nations. "The Saudis have given some positive signals on this as well to the U.N. envoy over the last 24 hours. The Emiratis also gave positive murmurs but the deal still has a little way to go," the Western diplomat said. The sources cautioned that the plan still needed agreement from all sides to the conflict, and would not, at least in its initial stages, result in an immediate ceasefire. In a statement on Thursday, Griffiths said he was "encouraged by the constructive engagement" of the Houthis and would be holding meetings with Yemen's internationally backed president, Abd Rabbuh Mansour Hadi. There was no immediate comment from the Saudi and Emirati embassies in Washington. Houthi representatives could not be reached for immediate comment. *This story was edited by Ahram Online