Syrian government and opposition delegates said talks to end their country's civil war have reached an impasse, with the United States and Russia backing the rival camps and trading accusations over the deadlock.
An opposition spokesman said on Friday that after five days of negotiations the talks reached a "dead end" because of the government's "belligerence," while Syria's deputy foreign minister said the opposition came to the table with an "unrealistic agenda."
However, both sides kept the door open for more negotiations, saying the talks may continue for another day.
The deadlock and accusations underscored just how far out of reach a political solution for Syria's civil war remains .
Some credit the talks, now in their second round in Geneva, with leading to an evacuation of hundreds of civilians from the embattled Syrian city of Homs. But other than that they yielded little more than acrimony.
That's largely because the Syrian delegates have a fundamentally different interpretation of what the talks are about.
The opposition wants the negotiations to focus on the formation of a transitional governing body that would administer the country until the next elections, while the government says the priority is for halting "terrorism."
Meanwhile, violence has escalated in Syria, with both sides blaming each other for a soaring death toll in a conflict that has killed more than 130,000 people and displaced millions in three years.
Louay Safi, a spokesman for the Syrian opposition delegation, told reporters "the negotiations are not moving toward a political solution," accusing the government side of "belligerence." He urged all parties, particularly the Russians who are the Assad government's biggest ally, to exert pressure on the government to break the deadlock.
"I deeply regret to say that this round did not achieve any progress," Syrian Deputy Foreign Minister Faisal Mekdad said. "We came to Geneva conference to implement Syria's declared position to reach a political solution. ... Unfortunately the other side came with another agenda, with an unrealistic agenda."
Earlier Russian Foreign Minister Sergei Lavrov accused the United States of using the talks for the sole purpose of "regime change," while US Secretary of State John Kerry suggested Moscow was backtracking on earlier commitments.
"The only thing they want to talk about is the establishment of a transitional governing body," Mr Lavrov said. "Only after that are they ready to discuss the urgent and most pressing problems, like terrorism," he added, speaking after meeting with the German foreign minister in Moscow.
Mr Kerry, who was in Beijing, said that agreeing on a transition government was the sole purpose of the Geneva talks. He said Mr Lavrov had stood up beside him several times when he had said that was the goal.
The UN temporarily suspended the evacuation of civilians from the embattled Syrian city of Homs on Friday, while the government screened military age males who left the area.
Meanwhile near Lebanon, Syrian forces and rebels clashed over the strategic town of Yabroud, causing hundreds of people to flee over the border.
The halt in evacuations came just a day after a ceasefire was extended for three more days. Hundreds more civilians are believed to still be trapped in a rebel-held medieval quarter known as Old Homs.
Senior Syria UN official Matthew Hollingworth said from Damascus that dozens of men and boys aged 15 to 55, who left Old Homs during earlier evacuations, are still being held and questioned by Syrian authorities.
"The agreement has been we will now concentrate on the process of completing the regularisation of status of the men from 15 to 55," Hollingworth said. "Only when that's done, will we look at another evacuation." Later in the day however he said the UN was not linking the next evacuation to the release of the men being processed by Syrian authorities.
The Syrian government considers males of military age to be potential combatants who must obtain security clearance before being released.