Geneva — The US said it will boycott Tuesday’s session of the Conference on Disarmament amid fear that Syria is using its presidency of the body to "normalise" the regime.

"Based on Syria’s repeated attempts last week to use its presidency of the Conference on Disarmament to normalise the regime and its unacceptable and dangerous behaviour, we are not participating in today’s session," Robert Wood, the US ambassador to the Geneva-based body, said in a statement. "We will continue to defend US’s interests" in the disarmament body.

Last week, Syria took over the body’s rotating, four-week presidency, which, according to a decades-old practice among its 65 member states, follows the alphabetical order of country names in English.

Wood was present during the first plenary session on Syria’s watch a week ago, when he took the opportunity to lead a number of countries to protest what he described as "a travesty".

Despite the mechanical nature of Syria’s arrival at the helm of the disarmament conference, following Switzerland and Sweden, a number of countries voiced their outrage that a representative of Damascus was presiding over the body that negotiated the chemical weapons ban.

Syria’s ambassador Hussam Edin Aala, meanwhile, slammed last week’s protest as "sensational propaganda" and "characterised by double-standards". More than 350,000 people have been killed and millions displaced since Syria’s civil war began in 2011 with the brutal repression of anti-government protests.

After hundreds of people died in chemical attacks near Damascus in 2013, a deal with Russia was struck to rid Syria of chemical weapons, staving off US air strikes. But the UN and Western countries have accused Damascus of carrying out a number of chemical attacks since then. A suspected chlorine and sarin attack in the Syrian town of Douma on April 7 this year triggered punitive missile strikes against alleged chemical weapons sites in Syria by the US, Britain and France.

Last week, Wood had briefly walked out of the room when Edin Aala took the floor, before returning to deliver a scathing speech. "Today marks a sad and shameful day in the history of this body," he told the assembly on May 29. He vowed at the time that throughout Syria’s presidency, the US would be represented "in this hall to ensure Syria is not able to advance initiatives that run counter to the interests of the US".

That was a promise the US has now backed away from, with no American representatives present during Tuesday’s session. But other nations were represented, with diplomats continuing to slam Syria over chemical weapons use.

The use of such weapons "under any circumstances is abhorrent and must be rigorously condemned", the representative for the EU, Anne Kemppainen told the gathering. "It is a war crime and may amount to a crime against humanity."

British representative Simon Cleobury, meanwhile, said his country, along with Australia, Bulgaria, Canada, France, Germany, Japan, New Zealand, Poland, Romania and the US, had called for "a special session of the Conference of the States Parties to the Chemical Weapons Convention". The meeting, he said, would "be a key moment for the international community to consider ways to strengthen the Organisation for the Prohibition of Chemical Weapons".

The global chemical arms watchdog, meanwhile, said the special session would take place in The Hague on June 26 and 27.