Donald Trump’s former national security adviser, John Bolton, says the US president faces a big challenge in reopening the Strait of Hormuz.

Bolton, who held the post in Trump’s first administration, says he has long supported the toppling of the Iranian regime, but told Today this morning he is worried about shortcomings in US strategy since the war began.

Bolton says keeping oil supplies flowing through the Strait of Hormuz should have been a priority when Trump ordered Operation Epic Fury.

The US military “should have been on it from the beginning,” he said.

“Having allowed the Strait of Hormuz to close … it is now incumbent on the US and Israel to reopen it.”

Bolton said it would probably take about two weeks for US and Western navies to clear the threat of attacks in the key waterway.