GENEVA/RIYADH (Reuters) - Yemen’s first round of peace talks in almost three years aims to build confidence between the warring sides, U.N. mediator Martin Griffiths said on Wednesday, playing down a delay in the arrival of one delegation.

Griffiths wants Yemen’s Saudi-backed government and the Iranian-aligned Houthi movement to work towards a deal to end the war, remove foreign forces from Yemeni territory, and establish a national unity government.

A Saudi-led coalition of Sunni Muslim Arab states backed by Western powers, including the United States and Britain, intervened in Yemen’s civil war in 2015 against the Houthis to restore the internationally recognized government of President Abd-Rabbu Mansour Hadi. Subsequent peace talks flopped.

Since then the humanitarian situation has worsened dramatically, putting 8.4 million people on the brink of starvation, triggering the world’s worst cholera epidemic, and wrecking the already weak economy.

Nobody knows how many people have died: the U.N. lost count more than two years ago, after 10,000 civilians were killed.

“The people of Yemen ... are desperately in need of a signal of hope. We’d like to think that the work we will do together in these next days will send a flickering signal of hope to them,” Griffiths said, adding that both sides had consistently pressed him for a release of prisoners.

Houthi leader Abdulmalik al-Houthi was “quite impatient for rapid progress”, Griffiths said.

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The Houthi movement’s al-Masirah TV reported the coalition had prevented the Houthi delegation from flying to Geneva. But Griffiths brushed off the delay, saying it was nothing unusual and he was confident it would be resolved.

He told reporters the first stage of talks would focus on how formal peace negotiations would work. The format was flexible and the two delegations did not need to be in the same room, he said.

“We need to discover ... what the parties are prepared to do and what they are prepared to prioritize, both in terms of substance, which will come in a later round, and in terms of these confidence building measures,” he said.

The U.N. Security Council urged both sides to de-escalate the conflict. Griffiths described the Council’s unity as “a huge asset”, adding that he did not expect a ceasefire but he hoped for no “provocative military events”.

Griffiths has already used the prospect of talks to forestall an attack by the Saudi-led coalition on Hodeidah, a port city and Yemen’s main supply line.

Aid workers say an assault on the port would be a catastrophe, and Griffiths has been in talks with the Houthis to hand control of it to the United Nations.

A draft U.N. peace plan seen by Reuters in June calls on the Houthis to give up their ballistic missiles in return for an end to the Saudi-led bombing campaign and a transitional governance agreement.

Anwar Gargash, minister of state for foreign affairs of the United Arab Emirates, part of the Saudi-led coalition, welcomed the talks. “Long way to go,” he wrote on Twitter. “But Geneva can bring outcome nearer.”