President Donald Trump said the US had carried out attacks against three nuclear sites in Iran, including the site in Fordo.
Trump posted on his Truth Social account that a "a full payload of bombs was dropped" on the site, that is known to be located several dozen meters underground, making it more difficult to attack.
According the post, all planes that took part in the strikes left Iranian airspace.
"Congratulations to our great American warriors," Trump said, adding that it is now "time for peace."
The impact of the strikes is still not clear.
Fordo — the heart of Iran's nuclear program
Situated on a former military base near the city of Ghom, Iran's leaders secretly installed the Fordo facility in the early 2000s.
That may be because a large part of the Fordo complex lies deep underground. To protect the site from possible attacks or sabotage and keep it out of view of IAEA inspectors, Iran had a system of 60-to-90-meter-deep tunnels (197 and 295 feet) drilled into the mountains.
International intelligence services first made the existence of the underground site public in 2009.
In 2012, the IAEA announced that scientists at Fordo had begun enriching uranium up to 20% "for medical purposes."
It is thought that a total of about 3,000 enrichment centrifuges have been installed at the underground site since then. Although Fordo is a smaller complex than Natanz, it is reportedly capable of producing purer grades of uranium, making it militarily far more significant.
Trump shares post with 'Fordo is gone'
After announcing the US Air Force's airstrikes on three nuclear sites in Iran, US President Donald Trump re-shared a post on Truth Social which labels the site in Fordo, an underground nuclear site in Iran, as "gone."
Despite carrying out airtsrikes on nuclear sites across Iran, Israel refrained from attacking the Fordo site.
US bunker-busting bombs, which uses weight and sheer kinetic force to reach deeply buried targets, were needed to reach the underground site.
Israel 'in full coordination' with US ahead of Iran strikes: report
Israel was kept in the loop ahead of the US airstrikes on three nuclear sites in Iran, Israeli public broadcaster Kan reported.
According to the report, the two countries were "in full coordination" ahead of the strikes.
Reports in Iran confirm Fordo strike
An Iranian official confirmed that part of the nuclear site in Fordo was attacked by "enemy airstrikes," according to Iran's Tasnim News Agency and IRNA agency.
Israel tightens restrictions following US attack in Iran
The Israeli army tightened restrictions across Israel as a precautionary measure following the US airstrikes in Iran.
Only "essential activity" will take place, while schools and other gatherings will be prohibited.
The measures are in effect as of 03:45 local time (02:45 CEST).
Reports: Trump not planning additional US strikes on Iran
US broadcaster CNN reported, citing unnamed sources, that President Donald Trump hopes the airstrikes carried out by the US Air Force would lead the way to new diplomatic efforts with Iran.
According to the report, the US is not planning additional strikes as of now.
NBC News also reported, citing White House officials, that Trump was expected to say in his address later that no additional strikes inside Iran were planned.
