SYRIA’S government has accused Britain, the United States and Turkey of supplying chemical agents to insurgents after discoveries in Damascus and Aleppo.

At a press conference on Wednesday, Deputy Foreign Minister Faisal Mikdad urged the Organisation for the Prohibition of Chemical Weapons (OPCW) to investigate the three countries over the allegations.

Mr Mikdad said the munitions found — tear-gas grenades — were made by two US companies and a British one.

“The special equipment found consisted of hand grenades and rounds for grenade launchers equipped with CS and CN toxic agents,” he said.

The chemical munitions were produced by the Federal Laboratories company in the US. The toxic agents were manufactured by British firm Chemring Defence and NonLethal Technologies, another US company.

The use of tear gas in war is banned under the 1993 Chemical Weapons Convention, to which Syria, the US, Britain, Turkey and all other nations except Israel, Egypt, South Sudan and North Korea are party.

Chemring’s published business policy commits it to “ensuring that we maintain a completely ethical stance in terms of the product and country combination of our products as defined in the group ethical policy and UK government legislation.”

A British Foreign Office spokesman told Russia’s Sputnik news: “The UK supplies no lethal equipment to any party in Syria.”

But even if this is true, Britain could have supplied the weapons to a third country that took a more active role in arming Syrian rebels.

The OPCW concluded its investigation of April’s Khan Sheikhoun chemical weapon attack in June, saying the nerve agent sarin had been found in samples from the town occupied by al-Qaidaaffiliated extremists.

The US, Britain and France blamed Syria for the incident, with US President Donald Trump ordering a cruise missile strike on a government air base.

Mr Mikdad announced that Syria had completed its own probe, which “conclusively determined that the so-called incident in Khan Sheikhoun from beginning to end was staged by militants according to a prearranged scenario.”

Insurgents were caught smuggling sarin gas across the border into Syria in 2013, acording to Turkish MP Eren Erdem.

Yesterday, two Syrian army columns advancing south from Ithriyah and north from Palmyra met up in the Syrian desert, isolating a 45-milewide pocket of Isis-occupied territory.

Government roops also advanced some 15 miles towards the town of Uqayribat at the centre of the pocket.