The Pentagon says it captured a chemical weapons expert from the so-called Islamic State (IS) and obtained key information for air strikes.
A spokesman said Sulayman Dawud al-Bakkar, also known as Abu Daoud, had been caught in Iraq in February.
The Pentagon said the capture had “removed a key IS leader from the battlefield”.
The US says it has begun more aggressive operations against IS in Iraq.
Daoud divulged details about IS chemical weapons facilities and production, as well as the people involved in it, Pentagon spokesman Peter Cook said.
The information led to multiple coalition air strikes that disrupted IS’s ability to manufacture chemical weapons, he said.
Daoud has now been transferred into Iraqi government custody, Mr Cook said.
US media reported on Wednesday the February arrest of an IS chemical weapons expert, but named him as Sleiman Daoud al-Afari.
They quoted Iraqi and US sources as saying he was a specialist in chemical and biological weapons for Saddam Hussein, the Iraqi leader overthrown by the US invasion in 2003.
He told interrogators how IS loaded mustard gas into shells, US sources told the New York Times.
At the time, the Pentagon refused to confirm the arrest.
Last month, sources at the global chemical watchdog, the Organisation for the Prohibition of Chemical Weapons (OPCW), announced that sulphur mustard had been used last year in an attack on Kurdish forces in Iraq blamed on IS.
If confirmed, it would be the first known use of chemical weapons in Iraq since the fall of Saddam.
Mustard gas, which is liquid at ambient temperature, is a powerful irritant and blistering agent which causes severe damage to the skin, eyes and respiratory system and internal organs.