Western officials, as well as allies in the Middle East, are trying to keep a close watch on what may be an ambitious and growing chemical weapons program by the Islamic State terror group.
French Prime Minister Manuel Valls issued the latest warning Thursday, following the terror attacks on Paris that left at least 129 people dead.
“We know and bear in mind that there is also a risk of chemical or bacteriological weapons,” Valls told parliament. “We must not rule anything out.”
WATCH: video of Valls and Talabani discussing the threat
Until now, some of the loudest concerns have been voiced by Kurdish officials, who repeatedly have accused Islamic State fighters of trying to employ chemical weapons in Iraq and Syria.
“They are in laboratories in Mosul and Raqqa, busy with making chemical weapons,” Kurdistan Regional Government Intelligence Agency director Lahur Talabani told VOA in an interview.
"God forbid that they have some sort of advanced chemical weapon; then things could get a lot worse than they are," he added.
U.S. officials, while concerned about Islamic State’s aggressive pursuit of lethal weapons, have been more cautious about its actual capabilities.
“It would not be surprising if ISIL has been able to fashion some crude chlorine based weapons — using common, readily available materials,” a U.S. counterterrorism official told VOA. “That said, it’s a long road between such makeshift weaponry and an actual chemical weapons program.”
A U.S. Defense Department spokesman said that, at least for now, there is "no confirmable nor actionable information" regarding the terror group's pursuit of a chemical or biological weapons program.
"We have always been concerned about ISIL's interest and intent to acquire any kind of chemical, biological or radiological weapons capability," said Major James Brindle. "We are continuing to investigate all these allegations very closely and to be proactive about the threat from chemical weapons or other similar threats."
Earlier this month, the Organization for the Prohibition of Chemical Weapons concluded that chemical weapons were used in fighting during August that involved Islamic State in Marea, north of Aleppo, Syria.
“The team was able to confirm with the utmost confidence that at least two people were exposed to sulfur mustard,” the report said. “It is additionally very likely that the effects of sulfur mustard resulted in the death of a baby.”
But the OPCW did not address the question of which warring party was responsible.
Just last month, Kurdish officials said blood tests of Peshmerga fighters who fought Islamic State near Irbil in August showed evidence they had been exposed to mustard gas, likely from mortar rounds containing the chemical.
The U.S. military also had been investigating claims of an alleged chemical weapon attack by Islamic State against Kurdish Peshmerga near Makhmur on August 11.
Brigadier General Kevin Killea with Combined Joint Task Force Operation Inherent Resolve said at the time that samples recovered by the Peshmerga had been sent to a "gold level laboratory, an international laboratory, for final analysis.”
Killea also tried to downplay concerns about whether U.S. forces in the region were prepared for the use of chemical weapons by Islamic State.
"The pre-deployment training that everybody goes through prepares them for the — the worst-case instances that you might imagine for chem [chemical], bio [biological], radiological events,” he told Pentagon reporters.
"We just have to monitor the situation and evaluate the threat, and address that threat level as it may or may not change,” said Killea.