The global chemical weapons watchdog says its inspectors in Syria have not been able to reach two sites because of security concerns.
In a statement, the Organisation for the Prohibition of Chemical Weapons (OPCW) said verification activities had been completed at 21 out of 23 sites.
"Efforts to ensure the conditions necessary for safe access to those sites will continue," the statement added.
The announcement means that the first in a series of tight deadlines on the path toward destroying Syria’s poison gas stockpile by mid-2014 has been missed.
The OPCW has not said who was responsible for the security concerns, only that negotiations to ensure the conditions necessary for safe access to the two remaining sites will continue, the BBC informs.