United Nations talks to end the conflict in Yemen have been postponed just four days before they were due to begin, a UN official told AFP news agency.

There had been growing uncertainty over which of the warring Yemeni parties would attend the talks, slated to begin on Thursday in Geneva, and the postponement is a further blow to UN efforts to broker peace in a country where nearly 2,000 people have been killed since March.

"I can confirm that the meeting has been postponed," the UN official told AFP, without providing further immediate explanation.

Underlining the difficulty of trying to get the rivals around the negotiating table, exiled Yemeni President Abd-Rabbu Mansour Hadi laid out his government's demands to attend the talks in a letter to UN Secretary-General Ban Ki-moon, insisting Shia Houthi rebels must withdraw from territory they have seized.

Hadi fled to the Saudi capital Riyadh along with his government in late March when rebels advanced on his southern stronghold, the port city of Aden.

He reiterated his position on Sunday during talks in Riyadh with the UN special envoy to Yemen, Ismail Ould Cheikh Ahmed.

The embattled leader demanded full implementation of UN Security Council Resolution 2216.

The April resolution called on the Houthis to relinquish territory they seized and surrender weapons they took from the army and other state institutions.

Aid trickles in

More than 545,000 people have been displaced in the Yemeni conflict and although some aid trickled in last week during a five-day ceasefire, people still lack basic needs, including water, electricity and fuel.

A ship carrying 460 tons of Emirati humanitarian aid docked on Sunday in Aden.
The shipment, including medical and food supplies, is the second from the United Arab Emirates following the delivery of 1,200 tons of aid last week, said local aid coordinator Ali al-Bikri.

Another ship carrying 400 tons of diesel also arrived on Friday, said Bikri, who was appointed by Yemen's government-in-exile.

"Aden needs urgently at least 200,000 food rations for the displaced," Bikri added.

Aden has been rocked by fierce fighting between the Houthi rebels backed by troops loyal to former president Ali Abdullah Saleh and southern fighters allied with the exiled Hadi.

PHOTO CAPTION

A boy and his sisters watch graffiti artists spray on a wall, commemorating the people killed in Saudi-led coalition airstrikes in Sanaa, Yemen, May 18, 2015.

Aljazeera