The United States launched a third night of strikes on Iran as President Donald Trump planned to reimpose a blockade Tuesday on Iranian ports and floated a 20% fee on cargo in the vital Strait of Hormuz.

Trump said a deal with the Islamic republic was still possible even as attacks were carried out, with Iran striking two ships in the strategic waterway and killing one crew member, according to the United Arab Emirates.

The US military said its five-hour mission hit targets across Iran including coastal Bushehr and Bandar Abbas, to “degrade Iran’s ability to attack commercial shipping”.

After the strikes, Iran’s Revolutionary Guards announced they had in turn fired missiles and drones on Bahrain, targeting a residential building for US forces and other facilities.

“We’re going to hit them very hard tonight, and we’re going to hit them hard tomorrow,” Trump said at the White House on Monday.

Trump’s declaration on the Hormuz blockade followed US and Iranian attacks of a scale unseen since an April ceasefire in the Middle East conflict, adding to doubts about efforts to bring a permanent end to the war.

Iran started blocking the strait after US-Israel attacks in February, which prompted Washington’s blockade on Tehran’s ports — but restrictions eased after the sides agreed a preliminary deal in June.

Trump said Monday that the United States was “taking over” the strait and would slap a levy of 20% on all cargo shipped through it, in an announcement that drew mockery from Iran and accusations of “piracy”.