UNITED NATIONS (Reuters) - The United Nations Yemen mediator said on Thursday he plans to invite the warring parties to Geneva on Sept. 6 to discuss a framework for peace talks and confidence-building measures as he tries to negotiate an end to the more than three-year conflict.

A proxy war is playing out in Yemen between Iran and Saudi Arabia. A Saudi-led military coalition intervened in Yemen in 2015, backing government forces fighting the Iran-allied Houthi group. Iran has denied supplying weapons to the Houthis.

During a U.N. Security Council briefing, U.N. mediator Martin Griffiths called on the parties to create a conducive environment to allow the Geneva consultations to take place.

“I am very conscious that each day costs lives which might have been saved,” Griffiths said.

The Houthi group said on Tuesday it is unilaterally halting attacks in the Red Sea for two weeks to support peace efforts, days after Saudi Arabia suspended oil exports through a strategic Red Sea channel following attacks on crude tankers.

Griffiths has recently been shuttling between the warring parties to avert a coalition assault on Hodeidah. It is home to the main port in the impoverished Arab country, where some 8 million people are believed to be on the verge of starvation.

“We have tried to find a way to avoid a battle for the city and the port of Hodeidah and we are still trying,” Griffiths told the council, adding that while the gap had been narrowed, he was still concerned that Hodeidah could be a flashpoint.

Air strikes on Thursday by the Saudi-led coalition on a fishing port and fish market in Hodeidah killed 26 people, Yemeni medical sources and aid agencies said.

“We’ve hit a new sense of urgency in Yemen,” U.S. Ambassador to the United Nations Nikki Haley told the council.

“If this is what’s starting to happen, civilians are at risk, infrastructure is at risk and we as the international community have to demand that the two parties come together and understand the seriousness of this,” Haley said.

She also again accused Iran of supporting the Houthis and condemned the Houthi missile attacks.

Independent U.N. sanctions monitors reported to the Security Council Yemen sanctions committee last week that they were investigating accusations from confidential sources that Iran was providing the Houthis $30 million worth of fuel a month.

“Iran has denied any involvement in any financial support to the Houthis,” they wrote in the confidential report, seen by Reuters.