The UN special envoy for Syria announced on Wednesday a "temporary pause" until February 25 of troubled talks in Switzerland aimed at ending the country's brutal civil war.
"I have concluded frankly that after the first week of preparatory talks there is more work to be done, not only by us but the stakeholders," Staffan de Mistura told reporters in Geneva.
"I have indicated from the first day I won't talk for the sake of talking. I therefore have taken the decision to bring a temporary pause. It is not the end or the failure of the talks," he said.
"Both sides indicated they are interested in having the political process started. I have already fixed a date for the next talks of 25th February."
His comments came after several days of fruitless talks aimed at starting indirect negotiations between the Syrian government and opposition.
The hoped-for six months of indirect "proximity talks" are part of an ambitious roadmap agreed by outside powers embroiled in the conflict in November in Vienna.
The opposition umbrella group High Negotiations Committee (HNC) only reluctantly arrived in Geneva on Saturday, a day after representatives from President Bashar al-Assad.
The HNC was insisting on immediate steps including humanitarian aid getting through to besieged cities, a halt to the bombardment of civilians and the release of prisoners.
It was also outraged that while in Geneva a major offensive by the Syrian army and allied militias was happening on the ground near Aleppo, backed by intense Russian air strikes.
In a major blow to the rebels, a military source said Wednesday that President Bashar al-Assad's army had cut the last supply route linking opposition forces in Aleppo to the Turkish border.
The government delegation meanwhile complained that the HNC was disorganised, had not named its negotiators and that the body contained individuals it considered "terrorists".
De Mistura said he was asking for the International Syria Support Group (ISSG) of outside countries to convene "as soon as possible."
The almost five-year-old civil war has killed more than 260,000 people, forced millions from their homes and sucked in a host of regional and global powers.