Sources close to Yemen's internationally recognized president, Abd Rabu Mansour Hadi, said the UN-backed peace talks taking place in the Swiss village of Macolin had failed.

Representatives of Iran-backed Houthi rebels and troops, along with militias loyal to Hadi, had been meeting since last Tuesday in a bid to stabilize a ceasefire which begun the same day. The ceasefire was put in place to ensure the safe delivery of urgently needed humanitarian aid.

Delegates at Macolin said progress had been "elusive." The talks had stalled over rival prisoner exchange demands.

The Reuters news agency quoted a source in Hadi's delegation as saying that talks would resume on 14 January.

Many thousands killed

Since March, when a Saudi-led alliance began air strikes against the rebels, more than 5,800 people have been killed and 27,000 wounded, according to the United Nations.

Late on Friday, UN special envoy Ismail Ould Cheikh Ahmed had said he was "deeply concerned at the numerous reports of violations of the cessation of hostilities."

The Houthis advanced from Yemen's north to occupy Sanaa in September 2014.

Earlier this week, the rebels claimed to have inflicted damage on a government coalition military base in Marib province east of Sanaa.

ipj/jlw (AFP, dpa, Reuters, AP)