The last batch of Syrian president Bashar al-Assad's declared chemical weapons have been sent out of Syria for destruction.
The news came as opponents claimed the regime had adapted by using chlorine gas against its opponents.
The remaining 7.2 per cent of Dr Assad's declared 1,300-tons of chemical weapons material was shipped from Syria's Latakia port today to be neutralised aboard the US vessel Cape Ray and then destroyed at commercial facilities in Europe and the US, the United Nations and the Organisation for the Prohibition of Chemical Weapons (OPCW) said in a joint statement.
While the Syrian government gave up its declared chemical agents and related materials, reports that the regime has been conducting chlorine-gas attacks have raised US, British and French concerns that Dr Assad has found a way to continue chemical attacks that indiscriminately kill and injure civilians.
Chlorine gas has many industrial uses, and is not listed in the Chemical Weapons Convention, the global treaty on chemical arms destruction. Even so, any proven use of a lethal chemical as a weapon is a violation of international law.
While congratulating the mission for achieving the milestone, US secretary of state John Kerry said "our work is not finished."
In addition to the reported use of chlorine gas, the US is concerned about delays in destroying some weapons production sites, Mr Kerry said today in Baghdad.
The milestone for the removal of declared stockpiles was achieved ahead of a June 30th deadline set by the UN, although the destruction of the materials will stretch beyond that date.
The executive council of OPCW still needs to decide how to proceed with the destruction of 12 former chemical-weapons facilities. Some are in a network of underground tunnels connected to other parts of a larger military complex, sparking a debate between Syria and the mission over how much damage their destruction would do to the rest of the base.
"While a major chapter in our endeavors closes today, OPCW's work in Syria will continue," OPCW director-general Ahmet Uzumcu said in a statement.
“We hope to conclude soon the clarification of certain aspects of the Syrian declaration and commence the destruction of certain structures that were used as chemical weapons production facilities.”
Today's landmark is a delayed success for an operation brokered by the US and Russia, which was meant to completely remove and destroy Syria's chemical weapons stockpile and facilities by June 30th.
The mission is several months behind schedule as fighting intensifies in the Syrian civil war and an increasing number of allegations are made against Dr Assad for attacks using undeclared chemical material such as chlorine.
The Assad regime agreed last year to surrender all its nerve gas and other weapons, as well as precursor chemicals, and ensure that they’re destroyed, to avoid a US military strike.
US president Barack Obama threatened a targeted strike after a sarin gas attack near Damascus killed 1,700 people in August.