NEW YORK (Reuters) - United Nations Yemen mediator Martin Griffiths and Iran’s Foreign Minister Mohammad Javad Zarif discussed on Monday how to make progress toward a nationwide ceasefire and reviving the political process in Yemen, a U.N. spokesman said. A Saudi-led military coalition intervened in Yemen in 2015, backing government forces fighting the Iran-aligned Houthis. The more than six-year long conflict is widely seen as a proxy conflict between Saudi Arabia and Iran. It is Griffiths first visit to Iran since becoming the U.N. envoy three years ago. Zarif and Griffiths “exchanged views on Yemen and how to make progress towards a resumption of the political process”, U.N. spokesman Stephane Dujarric said. “Mr Zarif and Mr Griffiths further discussed the urgent need to make progress towards a nationwide ceasefire, the opening of Sanaa airport and the easing of restrictions on Hodeidah ports.” He added that Griffiths welcomed Iran’s expression of support for the U.N. efforts to end the conflict in Yemen. While Griffiths office said the visit to Iran had been planned for some time, it comes after new U.S. President Joe Biden declared last week that the war in Yemen “has to end” and said Washington would halt support for the Saudi Arabia-led military campaign against the Houthis. The United States also said on Friday it intends to revoke its terrorist designation of the Houthis to avoid worsening Yemen’s humanitarian crisis. The United Nations describes Yemen as the world’s biggest humanitarian crisis, with 80% of its people in need and millions on the verge of famine.