The officials said the reinforcements were to come from an amphibious ready group and its Marine expeditionary unit, with one official adding that the group would be led by the Japan-based USS Tripoli, an amphibious assault ship.

 The unit headed by the USS Tripoli typically consists of around 5,000 sailors and Marines distributed across several warships. The development comes as President Donald Trump said US forces had "totally obliterated" Iranian military infrastructure on Kharg Island in the Strait of Hormuz, a critical waterway for global oil shipping. Retaliatory Iranian strikes targeting Israel and US military bases across the Middle East have disrupted major hubs for international air travel and caused the price of oil to soar.

Asked when the US Navy would start escorting tankers through the Strait of Hormuz, Trump told reporters on Friday: "It will happen soon". The movement of US personnel was first reported by the Wall Street Journal. It also reported that the request for reinforcements was made by US Central Command, the part of the US military responsible for the Middle East, and approved by Defence Secretary Pete Hegseth. The BBC has approached the US military and the Pentagon for comment, though future troop movements are usually not confirmed publicly

The US is also relocating parts of a missile defence system installed in South Korea to the Middle East, according to officials cited by the Washington Post and South Korean news outlets. Trump earlier said Iran would be hit "very hard" over the next week, adding that the war with Iran would be over when "I feel it in my bones". Hegseth also said the US military would show "no mercy for our enemies". The Pentagon this week said it had struck 6,000 Iranian targets over two weeks of conflict, which began when the US and Israel launched strikes on Iran on 28 February, killing Supreme Leader Ayatollah Ali Khamenei.

Iran's new supreme leader - and son of the former leader - 56-year-old Mojtaba Khamenei said Tehran would continue to block the Strait of Hormuz in his first public address on Thursday. In a statement read out by a newsreader on Iranian state TV, he vowed to "avenge the blood" of Iranians killed in the war with the US and Israel, and warned neighbouring countries to stop hosting US bases. (BBC)