US Secretary of State John Kerry has asked Russia to press its ally Syria into speeding up the removal of chemical weapons.
The US says only about 4% of chemical weapons declared by the Syrian government have so far been removed.
Mr Kerry raised the issue with Russian Foreign Minister Sergei Lavrov on the sidelines of the Munich Security Conference, officials said.
Syria’s chemical weapons are due to be removed and destroyed by 30 June.
Under the terms of the UN-backed plan, Syrian authorities are responsible for packing and safely transporting the chemical weapons to the Mediterranean port of Latakia.
The first consignment of 16 tonnes, from two Syrian sites, left Latakia on 7 January.
A further shipment left on 27 January, according to the Organisation for the Prohibition of Chemical Weapons (OPCW).
“Secretary Kerry pressed Foreign Minister Lavrov to push the regime for more progress on moving the remaining chemical weapons within Syria to the port in Latakia,” the US State Department official said.
Washington considered progress so far to be “unacceptable”, the official added.
The OPCW, which is overseeing the destruction of Syria’s chemical arsenal, has been meeting in The Hague to discuss the operation’s progress.
Courtesy BBC World News