U.S. Secretary of State John Kerry has called for a peace conference on Syria to be held urgently.
But he said peace will not be possible without a transitional government to replace the regime of President Bashar al-Assad.
Kerry said the United States believed that Assad "has lost the legitimacy necessary to be able to be a cohesive force that could bring people together, and that it is clear that in implementing Geneva-1, which is the only purpose for having the Geneva- conference now, that there has to be a transition government, there has to be a new governing entity in Syria in order to permit the possibility of peace."
Kerry was speaking on October 14 after meeting the UN and Arab League special envoy to Syria, Lakhdar Brahimi, in London.
Brahimi said he will travel to the Middle East this week to see representatives from all sides to try to set a specific date for the meeting.
"Very soon we've got now to set the precise date for that conference to start, and we look forward to everybody who can help the Syrians solve their problem being there," Brahimi said.
"And, of course, the Syrians themselves have to have a [central] place in that conference because the negotiations will be between them."
Meanwhile, Russian Foreign Minister Sergei Lavrov said on October 14 in Moscow that the United States should exert more pressure on the Syrian opposition to take part in the suggested peace talks in Geneva.
Lavrov said the West should "do their share of the work" to convene the conference.
First proposed in May, the so-called Geneva-2 peace conference has been repeatedly pushed back and is now expected to take place in mid-November.
George Sabra, the president of the Syrian National Council, the biggest member of the opposition National Coalition, said on October 13 the group would not attend the peace talks.
The more than 2 1/2-year-long Syrian conflict has left 115,000 people dead.
The Syrian government last month agreed to hand over its chemical weapons to international supervisors after the United States threatened military action in the wake of an August 21 sarin-gas attack that Washington says killed more than 1,400.
On October 14, Syria officially joined the UN convention banning chemical weapons. Around 60 experts from the UN-backed Organization for the Prohibition of Chemical Weapons (OPCW) are currently in Syria overseeing the destruction of its chemical-weapons stockpile.
OPCW spokesman Michael Luhan said the move came as a result of a decision made a few weeks ago at Syria's request to "fast-forward the application to enable us to get on with our work."
Also on October 14, the International Committee of the Red Cross said three of its six kidnapped staff members and a Syrian Red Crescent volunteer had been freed by their abductors in Syria.
Their release came a day after the aid workers were abducted within rebel-held territory of Syria's northwestern governorate of Idlib, near the border with Turkey.
The Red Cross said it was awaiting news on the fate of the remaining three abducted Red Cross workers.
The Red Cross, which does humanitarian work on both sides of Syria's conflict, said the team had traveled to Idlib on October 10 to deliver aid and assess the situation at health facilities there.
The group has not commented on the nationalities of those abducted. The Britain-based Syrian Observatory for Human Rights said an Al-Qaeda-linked rebel group, the Islamic State of Iraq and the Levant, was behind the kidnappings.
In other news, the Syrian Observatory for Human Rights said a car bomb killed at least 27 people in the town of Darkush in northwestern Syria, near the Turkish border.
With reporting by Reuters, AP, and AFP