What weapons and aircraft were used in the US attack on Iranian nuclear facilities?

(AFP) After days of uncertainty over a possible intervention, the United States struck and "completely and totally" destroyed Iran's nuclear facilities, President Donald Trump assured on Saturday.

The Republican leader had initially opted for the diplomatic route, with several rounds of negotiations between Washington and Tehran to try to reach a new agreement on the Iranian nuclear program.

However, in recent days, he had given mixed signals, weighing a possible intervention by his country in the war waged by its close ally Israel against Iran, while raising the possibility of returning to talks.

What weapons were used to attack the Iranian regime?

The United States used seven B-2 stealth bombers in strikes against nuclear facilities in Iran, Chairman of the Joint Chiefs of Staff Dan Caine said Sunday about "Operation Midnight Hammer."

The main strike group composed of seven B-2 Spirit bombers flew 18 hours from the U.S. mainland to Iran, with multiple in-flight refuelings, per Caine. "Iran's fighters did not fly, and it appears that Iran's surface-to-air missile systems did not see us. Throughout the mission, we retained the element of surprise," the general specified at a press conference.

According to Trump, several aircraft attacked three of the main Iranian nuclear facilities: Isfahan, Natanz and Fordow, on which a "full payload of bombs" was dropped.

The president gave no details about the weapons or ammunition used to attack the Iranian program. But given Fordow's subterranean configuration, it is likely that they were GBU-57 "bunker buster" bombs

According to the U.S. military, these 13-ton warheads can penetrate up to 200 feet deep before exploding.

They differ in that from most missiles or other bombs, which detonate on impact.

Testing of these weapons began in 2004, and Boeing won a contract in 2009 to install them on aircraft.

B-2 Spirit: Aircraft capable of transporting bunker buster bombs

The only aircraft capable of carrying GBU-57 bombs (two per plane) are the U.S. B-2 Spirit stealth bombers.

Before Sunday's attack, flight-tracking sites and The New York Times reported that several of these planes had taken off from the United States in westbound directions.

The B-2 Spirit can fly roughly 6,000 miles without refueling and is designed to "penetrate the enemy's most sophisticated defenses and threaten their most important and best-defended targets," according to the U.S. military.

The B-2 model was first introduced to the public in 1988, flew the following year and was delivered to the military in 1993.

It was deployed against Serbian forces in the 1990s, flying nonstop between Misuri and Kosovo, and again during the wars in Afghanistan and Iraq in the 2000s.