Yemen's exiled government has said it expects a deal shortly on a humanitarian ceasefire that would run through the Muslim Eid al-Fitr holiday later this month, as the capital Sanaa came under renewed air strikes.

The UN has been pushing for a halt to fighting and air strikes that have killed nearly 3,000 people in Yemen since March when a Saudi-led coalition intervened against Houthi forces in a bid to restore President Abd-Rabbu Mansour Hadi.

The government, exiled in Riyadh, said talks were focusing on carrying out an April UN resolution calling for the Iranian-allied Houthis to quit cities seized since September and for aid supplies to be sent to stricken Yemeni civilians.

"We are now in consultations for guarantees to ensure the success of the truce," Hadi spokesman Rajeh Badi said.

"The mechanism we presented to implement Resolution 2216 demanded real guarantees to ensure aid is delivered to those who need it," he said, noting that talks were under way to "lift the deliberate siege on Aden, Taiz, Lahj and Dhalea".

Major cities in central and southern Yemen have been racked by heavy fighting between the Houthis and a patchwork of military, regional and tribal forces allied with Hadi.

Badi said a sought-after "humanitarian pause" would last through the end of the three-day Eid, due to start on July 17.

The Houthis have also signalled readiness to honour a truce.

Houthi spokesman Mohammed Abdul Salam last week said in a Facebook post he had discussed the matter with UN Yemen envoy Ould Cheikh Ahmed in Muscat, Oman ,on Friday. Mr Cheikh Ahmed flew to Sanaa on Sunday for talks with the Houthis.

The UN last week designated the war in Yemen as a Level 3 humanitarian crisis, its most severe category, and the US and the EU have endorsed calls for a humanitarian suspension of hostilities.

On Friday, the UN alerted aid groups that a truce could start soon and advised them to be ready to start shipping aid. The UN engineered a five-day humanitarian ceasefire in May but aid groups said it did not last long enough to cover all of Yemen's needs.

In Sanaa, witnesses said several people were killed in Saudi-led air raids late on Sunday that wrecked the headquarters of the General People's Congress, the party of former president Ali Abdullah Saleh.

Mr Saleh retains the loyalty of major units of the Yemeni military and is an ally of the Houthis.