Syria Geneva II: UN to hold talks with rival groups
The UN mediator for Syrian peace talks, Lakhdar Brahimi, is to hold separate talks with rival delegations to assess their willingness to meet together.
The behind-the-scenes negotiations follow the first day of a major peace conference in Switzerland which ended in bitter divisions.
Mr Brahimi's initiative takes place before full talks resume on Friday.
It remains unclear whether the two sides will negotiate face-to-face - as planned by the UN - when talks restart.
BBC diplomatic correspondent Bridget Kendall, in Montreux, says that while the peace process may have got off to a rocky start - with heated disagreements on Wednesday - at least neither of the two rival delegations from the government and the opposition walked out.
And both say they will come to the UN brokered talks due to begin in Geneva on Friday.
But our correspondent says that how those talks will work is still not certain.
Mr Brahimi has revealed that he still does not know if the two sides are even prepared to sit in the same room.
He intends to consult them separately on Thursday to gauge what is possible.
"What we will try to do is talk about how to end this bloody war, and for that, I think, we have a kind of road map in the communique of 30 June 2012, and we'll see how we use that platform to best effect," Mr Brahimi said.
"We have no illusion that it is going to be easy, but we are going to try very hard."
Meanwhile, the head of al-Qaeda Ayman al-Zawahiri has called on rebel groups in northern Syria to stop fighting one another.
Clashes between rebels and the al-Qaeda-affiliated Islamic State of Iraq and the Levant (Isis) have been going on for three weeks. The UK-based Syrian Observatory for Human Rights said 1,400 people have died in the violence.
In an internet audio message, Mr al-Zawahiri called on "every free person in Syria seeking to overthrow Assad... to seek an end to fighting between brothers in jihad and Islam immediately".
If all goes well, the hope seems to be that the big political questions which they cannot agree on will be sidestepped, our correspondent says.
Instead concrete steps such as local truces and access for aid convoys in Syria will be discussed. But with the lack of trust on either side, even that may collapse into disagreements.
The BBC's Imogen Foulkes, who is at the conference, says that an immediate peace deal is not on the agenda. Neither is a transitional government nor the removal of President Bashar al-Assad.
Instead UN officials are hoping for anything that may bring some small relief to the millions of Syrians who have suffered so much - including the families of more than 100,000 people who have died in the conflict.
Iran, Syria's main ally in the region, has been excluded from the talks in Switzerland, despite earlier being invited by UN Secretary General Ban Ki-moon.
Speaking at the World Economic Forum in Davos, Iranian President Hassan Rouhani called for the Syrian opposition and government to sit round a table as the prelude to "free and fair elections".
It was for the Syrian people to decide their future, he added.
"No outside party or power can decide for the Syrian people and Syria as a country. We all have to help the people."
'Enough is enough'
At a fractious news conference in Switzerland late on Wednesday, during which there were repeated calls for calm, Mr Ban spoke of the suffering in Syria, saying: "Enough is enough. The time has come to negotiate."
He said that "the really hard work begins on Friday", adding: "We have a difficult road ahead, but it can be done and it must be done."
US Secretary of State John Kerry said: "There is no way - no way possible in the imagination - that the man who has led the brutal response to his own people could regain the legitimacy to govern."
However, earlier on Wednesday Syrian Information Minister Omran al-Zoubi told reporters: "There will be no transfer of power and President Bashar Assad is staying."
Another key sticking point is the Geneva I communique, agreed at a previous summit, which calls for a transitional government in Syria with full executive powers and which forms the basis of this new round of talks.
Syria has indicated that ending what it calls "terrorism" must be a priority of the communique.
But the head of the main opposition National Coalition, Ahmad Jarba, said the Syrian government must sign up to a deal to transfer powers.