Syria on Wednesday missed a deadline to hand over all the toxic materials it declared to the world's chemical weapons watchdog, putting the program several weeks behind schedule and jeopardizing a final 30 June deadline.
Under a deal reached in October between Russia and the United States, which helped avert a US-led missile strike against the regime of President Bashar Al-Assad, Syria agreed to give up its entire stockpile of chemical weapons by 5 February.
Russia said on Tuesday its ally Damascus would ship more chemicals soon, but Western diplomats said they saw no indications that further shipments were pending.
Syria has said it would submit a handover timetable to the Organisation for the Prohibition of Chemical Weapons (OPCW), which won the Nobel Peace Prize last year, but gave no indication of when that would happen.
There have been no additional shipments since 27 January and the latest deadline was missed, said OPCW spokesman Michael Luhan. "It's a status quo until we get this plan."
Syria had already missed a 31 December deadline to relinquish the most poisonous chemical agents, including mustard gas and sarin precursors.
So far, Syria has transported slightly more than four percent of the 1,300 metric tons it reported to the OPCW. The two small shipments of chemicals are being stored on a Danish vessel in the Mediterranean.
Under the US-Russian agreement, prompted by a sarin gas attack near Damascus that killed hundreds of civilians, Syria has until 30 June, or another five months, to completely eliminate its chemical weapons program.
Washington blames the poison attacks on the Al-Assad regime and threatened military retaliation.
Damascus has blamed the delay on security problems and the threat of attacks by rebels on road transports to the northern port of Latakia. It has requested additional armor and communications equipment.
But the United States and the United Nations, which is jointly overseeing the destruction program with the OPCW, said last week Syria has all the equipment it needs to carry out the operation and should proceed as quickly as possible.
The next major deadline is 31 March, by when the most toxic substances are supposed to be destroyed outside Syria, on a special US cargo vessel, the MV Cape Ray.
On Thursday, the head of the joint mission, Sigrid Kaag, will brief the United Nations about the operation in New York.