The Islamic State "is aggressively pursuing development of chemical weapons'' and is forming a team of dedicated experts who can help attain its leaders' dream of developing the weapon, US and Iraqi intelligence officials say.
Iraqi officials raised the concern that a large safe haven the extremists control since overrunning parts of Iraq and Syria last year has left Iraqi authorities largely in the dark over the ISIS weapons programme.
"They now have complete freedom to select locations for their labs and production sites and have a wide range of experts, both civilians and military, to aid them," a senior Iraqi intelligence official told The Associated Press.
The official, who has first-hand knowledge of the ISIS chemical weapons programme, spoke on condition of anonymity to discuss the sensitive information, said AP.
Iraqi authorities and the military have expressed such fear that the use of chemical weapon could be expanded that this early they have distributed gas masks to troops west and north of Baghdad, one general told the AP.
A senior officer in Salahuddin province, north of Baghdad, said 25 percent of the troops deployed there were equipped with masks.
Iraq's military also recently received from Russia 1,000 protective suits against chemical attacks, said Hakim al-Zamili, head of the Iraqi parliament's security and defense committee.
Citing intelligence reports he has access to, he said the group has managed to attract chemical experts from abroad as well as Iraqi experts, including those who once worked for Saddam Hussein's now-dissolved Military Industrialisation Authority. The foreigners include experts from Chechnya and Southeast Asia.
The senior intelligence officer disclosed the ISIS has set up a branch tasked with pursuing chemical weapons, and recently moved its research labs, experts and materials from Iraq to "secured locations" inside Syria, apparently out of concern of an eventual assault on Mosul, Iraq's second largest city, which was captured by ISIS in the summer of 2014.
The officer and two officials from another Iraqi intelligence agency have not given details of the programme.
Retired Lt. Gen. Richard Zahner, who was the top American military intelligence officer in Iraq in 2005 and 2006 and went on to lead the National Security Agency's electronic spying arm, noted that al-Qaeda tried for two decades to develop chemical weapons but didn't succeed due to technical and scientific difficulties.
However, he said, U.S. intelligence agencies have consistently underestimated the Islamic State group, which has shown itself to be more capable and innovative than al-Qaeda and has greater financial resources.
US intelligence officials believe the ISIS has the technological capability to produce nerve gas or biological agents.
In 2013, a senior deputy of the group's leader Abu Bakr al-Baghdadi wrote in his report that there was "significant progress" toward producing chemical weapons, according to two senior officials with access to the document obtained by Iraqi intelligence.
In it, the deputy, Sameer al-Khalifawy, wrote that chemical weapons would ensure "swift victory" and "terrorise our enemies."
But, he added, what was needed was "to secure a safe environment to carry out experiments.''