The US Central Intelligence Agency between 2005 and 2006 bought hundreds of nerve-agent rockets from a secret seller in Iraq as part of an effort to keep chemical weapons out of the hands of terrorists, according to a New York Times investigation.

In an effort dubbed Operation Avarice, the CIA worked with American troops in Iraq to buy and destroy at least 400 Borak rockets. Saddam Hussein’s government manufactured the rockets in the 1980s, along with other chemical weapons.

It is not known how much the US government paid for the weapons or who the seller was, though the Times did report that the seller was eager to get rid of his stash.

Many of the rockets were in poor condition and some were empty or held a nonlethal liquid, the report said. Other rockets contained the nerve agent sarin, which is among the most dangerous chemical weapons and was developed as a pesticide in Germany in 1938.

Further details of the purchase were difficult to come by, as Operation Avarice is still classified.

“Without speaking to any specific programs, it is fair to say that together with our coalition partners in Iraq, the U.S. military worked diligently to find and remove weapons that could be used against our troops and the Iraqi people,” Rear Adm. John Kirby, the Pentagon press secretary, said in a written statement, according to the Times.