Syria has publicly admitted for the first time that it possesses chemical and biological weapons, adding to international concern that its stocks could fall into the hands of militant groups as the country’s civil war intensifies.

As fierce fighting continued yesterday in Damascus and Aleppo, a foreign ministry representative told a press conference that “any chemical or bacterial weapon will never be used – and I repeat will never be used – during the crisis in Syria regardless of the developments”.

Such weapons are “stored and secured by Syrian military forces”, Jihad Makdissi said. But in what was seen as a veiled threat, he added that they would only be used in the event of “external aggression”. He also speculated that “terrorists” might deploy chemical weapons in Syria and try to blame regime forces.