The Islamic State group is aggressively pursuing development of chemical weapons, setting up a branch dedicated to research and experiments, according to Iraqi and US intelligence officials.

France’s Prime Minister Manual Valls spoke to the Parliament after the recent terrorist attacks in Paris, where death toll accounts 129 people. "We know that there could also be a risk of chemical or biological weapons. We must not rule anything out", he warned in his speech.

They are in laboratories in Mosul and Raqqa, busy with making chemical weapons, Kurdistan Regional Government Intelligence Agency director Lahur Talabani told Voice of America in an interview. In case they do have groundbreaking weapons, the situation could be much worse.

Although Washington is also expressing concerns over IGIL attempts to set up mass production of chemical weapons, it is rather skeptical about this possibility. US intelligence officials say they don't believe the IS has the technological capability to produce nerve gas or biological agents.

The only overt sign of the group's chemical weapons program has been the apparent use of mustard gas against Iraqi Kurdish fighters and in Syria. In mortars that hit Kurdish forces in northern Iraq earlier this year, preliminary tests by the US showed traces of the chemical agent sulfur mustard.