A chemical weapons expert working with Islamic State (IS) in Iraq has been killed in a coalition airstrike, the US military has said.

Abu Malik was killed near Mosul during an air raid on January 24th, US Central Command announced on Friday.

Malik had worked at a chemical weapons production plant under Saddam Hussein's regime before the dictator was toppled in 2003.

He later forged an affiliation with al Qaeda in Iraq in 2005, before joining IS, according to Central Command.

Malik's training "provided the terrorist group with expertise to pursue a chemical weapons capability", the military said in a statement.

"His death is expected to temporarily degrade and disrupt the terrorist network and diminish ISIL's ability to potentially produce and use chemical weapons against innocent people."

Previously US officials had not publicly referred to Malik as a key IS figure.

There has been no evidence to suggest IS possesses a major chemical weapons arsenal, but there have been claims the jihadist organisation has employed chlorine gas, which is classified as a "choking agent".

A US defence official, speaking anonymously, said Malik had been "involved in operations to produce chemical weapons in 2005, and planned attacks in Mosul with AQI (al-Qaeda in Iraq)".

"Based on his training and experience, he was judged to be capable of creating harmful and deadly chemical agents," added the official.

"We know ISIL is attempting to pursue a chemical weapons capability, but we have no definitive confirmation that ISIL currently possess chemical weapons."

The US-led coalition has carried out more than 2,000 air raids against IS in Iraq and Syria since August 8th. Airstrikes have been pounding the Mosul area in the north over the past week, the military said.