DUBAI (Reuters) - A air strike by the Saudi-led coalition against a radio station in Yemen’s Houthi-held port city of Hodeidah killed four people on Sunday, residents and medical sources said.

FILE PHOTO: A view of the gate of the Red Sea port of Hodeidah, Yemen August 5, 2018. REUTERS/Abduljabbar Zeyad/File Photo

The attack took place as U.N. officials engaged in shuttle diplomacy to arrange a resumption of peace talks in the four-year-old.

The Saudi-led coalition fighting the Houthis has intensified its air campaign and resumed an offensive to capture Hodeidah after U.N.-sponsored peace talks collapsed earlier this month when the Houthi delegation failed to show up.

The renewed attacks on the Red Sea port city, a lifeline for millions of Yemenis, could put further pressure on U.N. special envoy Martin Griffiths, who has said he will press ahead with diplomacy.

Four employees of the Almaraweah radio station were killed when coalition warplanes bombed its building, residents and medical sources told Reuters. The Houthis’ al-Massirah TV had said earlier that four employees were killed, three of them guards.

The coalition did not immediately respond to a Reuters request for comment.

The coalition of Sunni Muslim states, led by Saudi Arabia and the United Arab Emirates and armed by the West, has said taking control of Hodeidah would force the Iranian-aligned Houthi movement to the negotiating table by cutting off its main supply line.

Coalition-backed Yemeni forces last week seized the main road linking Hodeidah to the capital Sanaa as part of a strategy to isolate the two cities, both held by the Houthi group.

The United Nations is renewing efforts to end Yemen’s war under a peace plan that calls on the Houthis and the internationally-recognized government, backed by Saudi Arabia, to work on a peace deal under a transitional governing body.

Griffiths was visiting Sanaa on Sunday, the Houthi-controlled state news agency reported, the latest stop in another tour aiming to convince the Houthis to travel to Geneva for consultations that would lead to a peace agreement.

SABA said the United Nations struck an agreement to evacuate Houthi wounded by using Sanaa airport in a sign that diplomacy has started to pay off.

The Houthis did not show up in Geneva for talks earlier this month after they said their plane should be provided by a neutral party and should not be inspected by the coalition. They also asked to evacuate some of their wounded to Oman or Europe.

The alliance intervened in Yemen’s war, widely seen as a proxy conflict between Saudi Arabia and Iran, in 2015 to restore the internationally-recognized government of Abd-Rabbu Mansour Hadi, after he was ousted from Sanaa by the Houthis.