The missile attack came hours after the remains of a Revolutionary Guards commander killed by a U.S. drone strike were returned to his hometown for burial.

BAGHDAD — Iran attacked two bases in Iraq that house American troops with a barrage of missiles early Wednesday, Iranian official news media and United States officials said, the start of what Tehran had promised would be retaliation for the killing of a top Iranian commander.

“The fierce revenge by the Revolutionary Guards has begun,” the Islamic Revolutionary Guards Corps said in a statement on a Telegram messaging app channel.