A "series of powerful" attacks are being directed at Iran, the US military command Centcom said in a statement on X shortly after 11 p.m. on Tuesday, Swedish time.
The aim, according to the statement, is to provide a tangible response to Iran's attacks on "commercial vessels crewed by innocent civilians."
"The US attacks are a response to Iranian attacks on three commercial vessels operating in the Strait of Hormuz. Iran's demonstrated aggression was unjustified, dangerous and a clear violation of the ceasefire," Centcom writes.
Explosions in several places
Iran was earlier accused by Qatar and Saudi Arabia on Tuesday of attacking the three ships.
Iran's state radio and television company Irib reported about an hour after the American attacks began that six explosions were heard on the island of Qeshm, seven in the city of Sirik and an as yet unclear number in the port city of Bandar Abbas.
Iran calls the attacks a violation of the memorandum of understanding between the countries.
Warning from Iran
"Iran issues a serious warning about the consequences of the US's violation of the agreement and will take decisive measures to protect its interests and national security," Iran's Foreign Ministry said, according to Irib.
The US attacks follow the US Treasury Department's suspension of a waiver that temporarily lifted oil sanctions against Iran in mid-June.
At the end of June, the US targeted attacks on the same areas - Sirik and Qeshm - which are located on the Strait of Hormuz.
Formally, there has been a ceasefire between the US and Iran since a memorandum of understanding to end the war was signed in mid-June.
