A "full bomb load," 13-ton warheads... What we know about the US strikes on Iranian nuclear sites

The American president initially opted for the diplomatic route, with several rounds of negotiations between Washington and Tehran to try to reach a new pact on the Iranian nuclear program.

But in recent days he has been blowing hot and cold, weighing up a potential intervention by his country in the war that has pitted Iran against Israel since June 13, while also raising the possibility of returning to negotiations.

Here is what we know about this American offensive:

The sites hit

According to Donald Trump, planes struck three of Iran's main nuclear sites: Isfahan, Natanz and Fordo, on which a "full load of bombs" was dropped.

Built in violation of UN resolutions, the underground facility at Fordo (center) was presented by Tehran as a high-rate uranium enrichment plant capable of accommodating some 3,000 centrifuges.

This is where uranium particles enriched to 83.7% were detected in early 2023. Iran had cited "unintentional fluctuations" during the enrichment process.

Israel is unable to strike at such depths: only American aircraft are capable of carrying munitions penetrating enough to do so.

The Natanz plant (center) is undoubtedly the best-known of Iran's nuclear sites. Its existence was revealed in 2002.

It has two buildings, one underground and the other above ground, for a total of nearly 70 centrifuge cascades - more than 10,000 of these machines used to enrich uranium.

The Isfahan facility (center) is a conversion plant. It produces gases needed for uranium enrichment.

The weapons

Donald Trump did not provide details on the weapons used to strike the Iranian program . But given Fordo's underground configuration, GBU-57 bunker-buster bombs were likely dropped. These 13-ton warheads can penetrate up to 60 meters deep before exploding, according to the U.S. military.

This distinguishes them from most missiles or other bombs, which detonate on impact. Testing of these weapons began in 2004, and Boeing won a contract to install them on aircraft in 2009.

The planes

The only aircraft capable of carrying GBU-57s (two per aircraft) are the American B-2 Spirit stealth bombers.

Before Sunday's attack, flight tracking sites and The New York Times reported that several of the aircraft had departed from the United States, heading west .

The B-2 Spirit can fly 9,600 kilometers without refueling and is designed to "penetrate the enemy's most sophisticated defenses and threaten its most important and heavily defended targets," according to the U.S. military.

The B-2 model was first shown to the public in 1988, before flying the following year and being delivered to the Army in 1993.

It was deployed against Serbian forces in the 1990s, traveling back and forth between Missouri and Kosovo without stopping. Then it served in the wars in Afghanistan and Iraq in the 2000s.

And then?

Iran must "now agree to end this war," said Donald Trump, saying: "THE TIME FOR PEACE HAS COME."

He later claimed in a speech to the nation that all of Iran's nuclear enrichment facilities were "completely destroyed."

"Remember, there are many targets left, tonight's was by far the most difficult of all (...). But if peace does not come soon, we will target these other targets with precision, speed and skill," he warned.

The US attacks "will not stop" Tehran's nuclear activities, the Iranian atomic agency responded, describing them as a "barbaric act" .

Israel, for its part, thanked the American president for helping to achieve "peace through strength" , with its Prime Minister Benjamin Netanyahu seeing the Middle East at a "historic turning point" .

UN Secretary-General Antonio Guterres has expressed concern about a "dangerous escalation" that represents a "direct threat to peace and security in the world."