Syrian peace talks were due to resume in Geneva on Tuesday with the warring sides deadlocked over the explosive issue of transferring power from President Bashar al-Assad's regime.
UN mediator Lakhdar Brahimi admitted as the talks closed on Monday that the negotiations "haven't produced much". But he said he would bring the country's warring sides together again on Tuesday for another attempt at political discussions.
"Tomorrow we are going to put forward the Geneva communique... Then we are going to decide with them how we are going to proceed in discussing its many elements," he said, in reference to a text agreed by world powers in 2012 that calls for the creation of a transitional governing body in Syria.
"We are doing what the situation allows, what the market can bear," he told reporters when pressed on the slow pace of peace efforts.
Monday marked the third day of UN-sponsored talks between the two sides in Geneva and the first dealing with political issues.
The two sides have been brought together in the biggest diplomatic push yet to end a civil war that has left more than 130,000 dead and forced millions from their homes.
Monday's session broke up quickly after the regime set out a statement of principles that did not deal with a political transition and was immediately rejected by the opposition.
Regime delegation member Buthaina Shaaban said the government had presented "political principles which we thought no two Syrian persons should disagree with" -- including protecting the country's sovereignty, preserving state institutions and stopping the threat from "terrorist" groups.
"We were surprised that this basic paper was rejected by the other side," she said.
Rima Fleihan, a member of the opposition National Coalition's delegation, said: "The discussions were not constructive today because of the regime's strategy to deflect... (and) change the subject by talking of terrorism."
Officials on both sides said they had no plans to leave the talks however.
"We are not relying on the government side, we know their way, we hope they will start to change it... We are going to be patient," said Louay Safi, a member of the opposition delegation.
The opposition says President Bashar al-Assad must leave power and a transitional government be formed based on the agreement reached during a first peace conference in Geneva in 2012.
The regime says Assad's role is not up for debate at this conference -- dubbed Geneva II -- and denies that the initial Geneva deal requires him to go.
In Damascus, official Syrian media made it clear that Assad's continued leadership remained a line that negotiators would not cross.
The regime accuses the opposition and its international backers of promoting "terrorism" in the country, pointing to militant Islamist rebel groups like the Islamic State of Iraq and the Levant (ISIL) and the Al-Nusra Front.
'No concrete step' on Homs relief
In the first tangible promise to emerge from the talks, Brahimi said Sunday the regime had agreed to allow women and children safe passage from besieged rebel-held areas of the city of Homs.
The regime's promise raised some hopes of humanitarian relief, but was greeted by scepticism on the ground.
Activists in rebel areas of Homs said residents had "no trust" in the regime and first wanted aid supplies and guarantees that those leaving would not be arrested.
The opposition also raised concerns about a regime demand to receive a list of names of men who want to leave, saying this was part of intelligence gathering.
The Old City of Homs has been under siege since June 2012 after rebels there rose against the regime, with an estimated 500 families living with near-daily shelling and the barest of supplies.
Brahimi has also expressed hope that a convoy of humanitarian aid will be allowed to enter the besieged area on Monday, saying rebel forces had already agreed and the local governor was considering the issue.
The Red Cross said there had been "no concrete step" to provide humanitarian relief in Homs on Monday.