The last of Syria's declared chemical weapons have been removed from the country and are destined to be destroyed at sea according to the world's chemical weapons watchdog.

Ahmet Uzumcu, head of the Organisation for the Prohibition of Chemical Weapons, told a press conference in The Hague "as we speak, the ship has just left the port [of Latakia]".

"Removing the stockpile of precursor and other chemicals has been a fundamental condition in the programme to eliminate Syria's chemical weapons programme," Mr Uzumcu said.

Syria had previously shipped out 92% of its stockpile of chemical weapons under the terms of an UN-backed and US-Russia brokered agreement last year.

However, the remaining 8% of the stockpile remained at one site with the Syrian government claiming it was unable to transport it to Latakia because of security concerns.

The deal was reached after a sarin nerve gas attack in a rebel-held Damascus suburb killed around 1,400 people.

The Syrian government agreed to hand over its chemical arsenal after the US threatened airstrikes against Mr Assad's regime in response.

A Danish ship is taking chemicals to Italy's port of Gioia Tauro where they will be transferred to the US ship Cape Ray for destruction at sea, while some chemicals are to be destroyed at sites including in the US and Britain.

Despite the removal of these weapons an OPCW investigation team said last week that chemical agents such as chlorine, which Syria has not been obliged to hand over, have recently been used "in a systematic manner."

The OPCW team probing alleged chlorine use was attacked with a roadside bomb and gunfire on 27 May, preventing them accessing the site of an alleged attack in the village of Kafr Zeyta.

Despite not being able to visit the alleged site of the chlorine attack, OPCW officials spoke to doctors in Kafr Zeyta "and obtained their verbal medical reports relating to the treatment of individuals allegedly affected by exposure to chlorine".

The chlorine probe came after France and the US alleged that Mr Assad's forces may have unleashed industrial chemicals on several rebel-held villages in recent months.

Syria did not have to declare its stockpile of chlorine - a weak toxic agent that can be considered a chemical weapon if used offensively - as part of the disarmament deal as it is widely used for commercial and domestic purposes.