The United States carried out airstrikes against five locations in Iraq and Syria on Sunday, targeting multiple weapons and munitions depots linked to Iran, two U.S. officials said.
The weapons and lethal aid stored at the sites had been used in a series of recent attacks on bases of the U.S.-led coalition fighting the Islamic State group in Iraq and Syria, the officials said.
The officials said a series of significant secondary explosions seen at the sites indicated that munitions and explosives had likely been struck. It wasn't immediately clear whether anyone was killed or injured.
No one has claimed responsibility in the attack, but The Associated Press reported that the Al Qaeda-linked group has often carried out similar bombings, including one in October 2017 that killed 500 people.
Courtney Kube is a correspondent covering national security and the military for the NBC News Investigative Unit.
Tim Stelloh is a reporter for NBC News, based in California.