Peace negotiations between Yemen's warring factions in Switzerland ended without agreement and will resume in mid-January as heavy fighting continued in the country.

Fierce clashes and air strikes by a Saudi-led coalition pounded northern Yemen on Saturday, as the two main parties in the country's nine-month conflict continued to violate a ceasefire.

"We have decided to hold the next round of talks on January 14," UN special envoy Ismail Ould Cheikh Ahmed told reporters, adding that the location of the next round had yet to be decided.

Speaking from Bern, Ould Cheikh Ahmed said a week-long ceasefire that began last Monday was not respected in some parts of Yemen, but added that the talks had made "serious progress".

Both sides agreed on a negotiating framework, on setting up a joint de-escalation committee, and they worked on a package of confidence-building measures, he added.

"We are far from a ceasefire," he said about the truce that has been frequently violated, adding that he has requested both parties to prolong the ceasefire.

'Failed negotiations'

Earlier on Sunday, delegates from the two sides said substantial progress had proved elusive.

"The negotiations have basically failed," said a source with the delegation representing both the Iran-backed Houthi Shia rebels and renegade troops loyal to wealthy ex-president Ali Abdullah Saleh.

He told AFP news agency the ceasefire, which was meant to facilitate the delivery of desperately needed humanitarian aid, was "still-born".

"We have not achieved any results," agreed a source in President Abd-Rabbu Mansour Hadi's government delegation.

Independent journalist Iona Craig described the outcome of the first round of peace talks as an "agreement to keep talking".

"By agreeing to go along with the UN and international community in this means that they can just keep fighting. So at the moment, that commitment to peace talks or political negotiations appears to be just minimal - enough to keep the pressure off them so that they can then go back and just keep fighting," Craig told Al Jazeera.

"It's hard to be optimistic that really they are any closer to reaching a political deal or settlement that will result in a long-term ceasefire," she added.

Since March, Saudi Arabia has led an Arab coalition whose warplanes and troops have supported President Hadi against the rebels, who have seized the capital and other areas.

More than 5,800 people have been killed - about half of them civilians - and about 27,000 wounded in Yemen since then, according to UN figures.

Al Jazeera