A specially equipped US ship has finished neutralising all 600 metric tons of the most dangerous of Syria’s chemical weapons components surrendered to the international community this year to avert threatened air strikes, the Pentagon said on Monday.

It said the Cape Ray, equipped with the US-developed Field Deployable Hydrolysis System, neutralised 581.5 metric tons of DF, a sarin precursor chemical, and 19.8 metric tons of HD, an ingredient of sulphur mustard, while afloat in the Mediterranean.

The vessel will travel to Finland and Germany in the next two weeks to unload the resulting effluent, which will be treated as industrial waste to render it safer, a Pentagon spokeswoman said.

It was the first time chemical weapons components had been neutralised at sea, the Pentagon said.

The vessel will travel to Finland and Germany in the next two weeks to unload the effluent

Damascus agreed in September to a Russian proposal to give up its chemical weapons to avert threatened military strikes by the United States and France, which accused Syria of using the arms against opponents of President Bashar al-Assad.

A number of countries are involved in eliminating the chemical stockpiles.

The US was selected to dispose of the worst of the chemical weapons components because it had recently developed a mobile version of the hydrolysis system it uses for neutralising chemical stockpiles.

The system uses substances and mixtures such as water, sodium hydroxide and sodium hypochlorite to neutralize bulk amounts of chemical warfare agents, according to the US Army’s Edgewood Chemical Biological Centre.

Earlier this year, the hydrolysis system was placed aboard the Cape Ray, a 648-foot (198-metre) vessel that is part of the US Maritime Administration’s ready reserve force of 46 ships.

The ship was held at Rota, Spain, for several months due to Syrian delays in handing over its declared stockpiles of chemical agents.

The Cape Ray began neutralising the chemicals after picking them up from Italy in late June.