Syria will miss a December 31 deadline for the removal of part of its chemical weapons arsenal for destruction, but international inspectors insisted the overall mission was still on track.
The delay came as the Syrian Observatory for Human Rights said more than 130,000 people had been killed since the conflict began in March 2011, with the overwhelming majority of casualties caused by conventional arms.
The prospects for a peace conference scheduled for next month meanwhile appeared to dim further, with a Syrian newspaper reporting that the delivery of invitations to the meeting had been delayed.
Syria had been due to turn over some of the deadliest chemicals in its arsenals to several ships by the end of the year, for delivery to a US boat which will destroy the materials at sea.
But a Norwegian frigate and a Danish warship that had been waiting off the Syrian coast returned to port in Cyprus on Monday night as it became clear that the removal mission would not go ahead as scheduled.
Lars Hovtun, a spokesman for the Norwegian ship HNoMS Helge Ingstad gave no new date for the mission to escort the dangerous cargo out of Syria.
"We are still on high alert to go into Syria," he said. "We still don't know exactly when the orders will come."
The international disarmament mission in Syria had acknowledged on Saturday it was "unlikely" the weapons could be transported to the Latakia port in time for the December 31 deadline.
But the Organisation for the Prohibition of Chemical Weapons remained positive on Tuesday, saying the overall plan to rid Syria of its chemical arsenal was on track.
"An enormous amount of work has been accomplished in three months," OPCW spokesman Christian Chartier told AFP.
"Syria's chemical arsenal has been completely neutralised, the chemical agents and chemical products are under international control, have been sealed... The effective dismantling of the production and filling plants is on course."
"All unfilled munitions have been destroyed, so even if the Syrians tried to get their hands on certain chemical products they wouldn't have the weapons to use them," Chartier said.
"Their capacity to produce and use chemical weapons has been reduced to zero."
Chartier said the operation was still on track to meet a deadline to rid Syria of its chemical arsenal by mid-2014.
"The most important deadline in our eyes is June 30, and nothing leads us to believe that it won't be met," he said.
The failure to meet the December 31 deadline underscored the complexity of the task of eradicating Syria's vast chemical arsenal in the middle of a civil war.
Death toll passes 130,000
The Syrian Observatory for Human Rights, a Britain-based group that relies on a network of sources inside Syria, said Tuesday that the death toll from nearly three years of war now stood at 130,433 people, including some 46,266 civilians.
The dead also include 29,083 opposition fighters and jihadists, and 52,290 pro-government forces, among them soldiers, Syria militiamen and fighters from Lebanon's Shiite Hezbollah movement.
The deaths include hundreds killed in an August 21 chemical weapons attack outside Damascus, which saw the United States threaten military action against Syria in response.
The threat was headed off by a US-Russian deal under which Syria joined the Chemical Weapons Convention and agreed to turn over its chemical weapons for destruction.
Syria's Prime Minister Wael al-Halqi, addressing parliament on Tuesday, said the government was complying with its obligations.
"We were able to accomplish what was agreed upon, destroying the chemical production and mixing sites," he said.
"Now we have started collecting these materials so they can be transferred to the Syrian ports and taken to other places and destroyed within a timeframe that Syria has committed to."
On the diplomatic front, Syria's Al-Watan newspaper quoted a foreign ministry source as saying invitations to the peace conference scheduled for January 22 in the Swiss town of Montreux had not been sent.
The source said invites were to have been sent by December 28, and the delay was "the result of the floundering efforts to form a delegation representing the 'opposition'."
The key opposition National Coalition has yet to officially announce it is attending the conference, and there are questions about whether staunch regime ally Iran will be invited.
In Aleppo city meanwhile, the Observatory said 10 people, including two children, were killed when a regime tank shell hit a bus.
The monitoring group said the toll could rise as many of those injured were in critical condition.