Delegations from both warring parties in Sudan are present in Geneva for talks with a UN envoy, though one side has yet to turn up to meetings, the United Nations said Friday.

War has raged since April 2023 between the Sudanese regular army under Abdel Fattah al-Burhan and the paramilitary Rapid Support Forces, led by his former deputy Mohamed Hamdan Daglo.

UN Secretary-General Antonio Guterres's personal envoy for Sudan, Ramtane Lamamra, invited delegations from the army and the RSF for talks in Geneva, focused on humanitarian aid and protecting civilians, UN spokeswoman Alessandra Vellucci told a media briefing.

Despite being present in the Swiss city, one side did not show up for Thursday's first day of discussions, she said, without identifying which party.

The talks are taking place under the so-called proximity format, whereby Lamamra will separately meet with one delegation at a time, in different rooms. The two delegations are not scheduled to meet each other.

"The personal envoy has started the discussion, yesterday; indeed one of the parties didn't show up, but they are here in Geneva," Vellucci said.

"I can't give you the details on which warring party has showed up or not," she told reporters.

"We urge both parties to participate in the discussions.

The talks are in Geneva, with some of them taking place at the UN's Palais des Nations headquarters, said Vellucci. No end date has been scheduled.

- Local ceasefire options -

The talks come on the back of two UN Security Council resolutions on Sudan passed earlier this year.

"The focus is based on the resolutions: measures to be undertaken to ensure the distribution of humanitarian assistance to all the Sudanese population in need, and options to ensure the protection of civilians across Sudan," said Vellucci.

"The discussions seek to identify avenues for advancement of the identified humanitarian and protection of civilians measures, through possible local ceasefires, as requested by the Security Council."

Vellucci said the two delegations were comprised of senior representatives of the warring parties and include humanitarian, security and military experts.

"The humanitarian situation in Sudan is deteriorating by the day, so we really need to look at the devastating impact this has on the civilian population -- and we urge the delegations to rise up to this challenge and engage in constructive discussions," she said.

Lamamra, 72, is a former deputy prime minister of Algeria and was also the foreign minister. He was previously the African Union's commissioner for peace and security between 2008 and 2013.

The conflict in Sudan has left tens of thousands dead and displaced more than 10 million people, according to the United Nations.

A recent UN-backed report said nearly 26 million people, or slightly more than half of the population, were facing high levels of "acute food insecurity".