Washington — Senior Pentagon officials revealed new details about the U.S. operation to bomb three nuclear sites in Iran, with the chairman of the Joint Chiefs of Staff saying it was the “largest B-2 operational strike in U.S. history” and inflicted “extremely severe damage and destruction” to the targets.

“This was a highly classified mission with very few people in Washington knowing the timing or nature of this plan,” Gen. Dan Caine, the chairman, said in a briefing at the Pentagon on Sunday morning detailing the strikes against the Iranian nuclear sites at Fordo, Natanz and Isfahan.

Caine said the mission, dubbed Operation Midnight Hammer, included seven B-2 Spirit bombers that flew east from Whiteman Air Force Base in Missouri to Iran. Another group of B-2s flew west over the Pacific to act as decoys — news reports emerged over the course of the day Saturday that a group of the bombers were headed to the U.S. base in Guam.

Meanwhile, the 18-hour flight east by the bombers that would drop payloads on Iran required multiple in-flight refuelings as the planes crossed the Atlantic and the Mediterranean. The bombers met up with U.S. fighter jets and support aircraft once over land in the Middle East, executing a “complex, тιԍнтly timed maneuver,” Caine said.