A third shipment of chemical weapons material left Syria on Monday under a deal to rid the country of its arsenal by mid-2014, the mission overseeing the operation said.
The joint United Nations-Organisation for the Prohibition of Chemical Weapons (OPCW) mission did not give details about the shipment but said it left on a Norwegian cargo vessel, escorted by ships from four countries.
"The Joint Mission confirms that in-country destruction of some chemical materials has taken place alongside the removal of chemical weapons material, and welcomes progress to date," it said in a statement.
"The Syrian Arab Republic is encouraged to expedite systematic, predictable and high-volume movements to complete the safe removal of chemical materials," it added.
Under a UN resolution that cemented a deal worked out by the United States and Russia, Damascus is to give up all its chemical weapons for destruction by June 30.
But progress has slowed considerably in recent months, and the UN Security Council last week demanded that Syria move faster in the process of dismantling its arsenal of the banned weapons.
Syria has missed several deadlines for removing material, and -- prior to the shipment Monday -- was estimated by Washington to have shipped out just five percent of its stockpile.
Damascus blames the delays on insecurity in the country, where the government is locked in a brutal war with rebels seeking President Bashar al-Assad's overthrow.
But the Security Council last week said "Syria has sufficient material and equipment" as well as "substantial international support" to meet the deadlines.
In a statement, the OPCW's director general Ahmet Uzumcu said he hoped the latest shipment would "generate new momentum" for the operation.
"A significant effort is needed to ensure the chemicals that still remain in Syria are removed -- in accordance with a concrete schedule and without further delay -- consistent with the obligations of the Syrian Arab Republic," he said.
The deal to destroy Syria's chemical arms came after an August 2013 chemical weapons attack on the outskirts of Damascus that reportedly killed hundreds of civilians.
Washington and the opposition blamed the attack on the regime, which has denied responsibility.