Syrian National Council rejects Geneva peace talks
The largest group in Syria's opposition coalition says it will not take part in proposed peace negotiations in Geneva.
Syrian National Council leader George Sabra said the group would pull out of the umbrella coalition if it took part in the talks.
He said his faction would not negotiate with the Syrian government, adding that conditions for talks were not right while Syrians continued to suffer.
The UN, US and Russia want the long-delayed talks to be held next month.
Anger at international response
Mr Sabra told French news agency AFP that the Syrian National Council (SNC) "had taken the firm decision... not to go to Geneva under the present circumstances (on the ground)".
"Ghouta (agricultural belt around Damascus) is under siege and it is forbidden to even bring in bread. Are these the conditions that will allow us to achieve... a democratic transition in Syria?" he asked.
Mr Sabra was also fiercely critical of the international community, accusing it of failing to punish the Syrian government after the 21 August poison gas attack that killed hundreds of civilians near Damascus.
The Syrian government and military deny they were involved.
"The international community has focused on the murder weapon, which is the chemical weapons, and left the murderer unpunished and forgotten the victims," he added.
The SNC was the original main opposition group outside Syria but broadened almost a year ago into a wider coalition, of which it still remains the biggest component.
Mr Sabra's statement came as US Secretary of State John Kerry was preparing to meet United Nations and Arab League peace envoy Lakhdar Brahimi in London on Monday.
The Syrian government has already agreed to attend peace talks, as has Ahmed Jarba, the leader of the umbrella opposition coalition.
George Sabra's declaration underlines the difficult task facing the Americans in trying to get a unified and credible opposition delegation to take part, says the BBC's Jim Muir in Beirut.
Mr Jarba has faced a storm of protest within the coalition leadership, our correspondent says, with the group already accused of being out of touch with the situation on the ground.
Several of the major rebel fighting groups have renounced the coalition and have rejected the idea of talks.
Meanwhile, more radical groups, who are allied to al-Qaeda and reject democracy altogether, have been told by its leader Ayman al-Zawahiri not to compromise and keep fighting for an Islamic state.
Also on Sunday, Syrian state-run TV reported that an International Red Cross mission had come under attack in the north-western province of Idlib, with some workers "abducted".
A spokesman for the Red Cross, Ewan Watson, said he could not confirm or deny the report but was in the process of finding out the facts.
Separately, Syria's Red Crescent reportedly said on Sunday it had evacuated at least 1,500 people over the weekend from a rebel-held Damascus suburb besieged by the army for months.
"Around 1,500 people, most of them women and children, were evacuated from a point on the outskirts of Muadhamiya al-Sham and taken to shelters," Red Crescent head of operations Khaled Erksoussi told AFP.
More than 100,000 people have been killed since the uprising against President Assad began in March 2011, according to the UN.
Earlier this month, the UN estimated that more than eight million Syrians could have been forced from their homes by the country's civil war by the end of 2014.
No date has been fixed for peace talks, but they are expected in the middle of next month.