A chemical weapons expert from the Islamic State (IS) group in Iraq has been captured by US special forces and is being questioned, officials say.
The man was once a specialist in chemical and biological weapons for Saddam Hussein, the Iraqi leader overthrown by the US invasion in 2003, Iraqi and US sources told US media.
Named as Sleiman Daoud al-Afari, he was seized by US special forces last month.
The US special forces are part of a more aggressive strategy against IS.
The man has already told interrogators how IS loaded mustard gas into shells, US sources told the New York Times.
Mr Afari was identified as a former employee of the Military Industrialisation Authority, which functioned under Saddam, who used poison gas against Iraq’s Kurdish community in the 1980s.
Unnamed US defence sources told the New York Times Mr Afari was being held in Irbil, a Kurdish stronghold in northern Iraq.
He is being questioned about IS plans to use mustard gas, which is banned under international law, in Iraq and Syria, the paper says.
The alleged IS weapons expert reportedly gave his captors details of how the group had weaponised mustard gas into powdered form and loaded it into artillery shells.
Two unnamed Iraqi intelligence sources quoted by the Associated Press news agency described Mr Afari as the head of the IS unit trying to develop chemical weapons.