Donald Trump has threatened that Iran will be “blown off the face of the earth” if it attacks US vessels trying to reopen a route through the strait of Hormuz.

The US launched an operation on Monday to help hundreds of ships trapped with their crews in the Gulf, dragging the region back to the brink of full-scale war.

Tehran sought to reassert its blockade on the strait, which is a vital waterway in global trade. While the US military claimed to have destroyed six Iranian small boats and intercepted both Iranian cruise missiles and drones, this was denied by Iran.

Over 800 ships and roughly 20,000 crew members remain stranded in the region.

The US president issued the threat in an interview with Fox News on Monday where he also described the ongoing US naval effort as “one of the greatest military maneuvers ever done”, and claimed that Iranian officials had been “far more malleable” in recent talks than before.

Addressing concerns about American weapons stockpiles, he told Fox News: “We have more weapons and ammunition at a much higher grade than we had before.

“We have the best equipment. We have stuff all over the world. We have these bases all over the world. They’re all stocked up with equipment. We can use all of that stuff, and we will, if we need it,” he added.

His threats against Iran echo remarks he made in April, when he warned that a “whole civilization will die” if Tehran failed to comply with his demands over the strait of Hormuz – comments that drew widespread domestic and international backlash.

His comments call into question the fragile, Pakistan-brokered ceasefire that halted hostilities last month, but failed to open up the strait of Hormuz, through which about a fifth of international oil supplies usually travel.

Earlier on Monday, Iran’s military central command warned that it would strike any US naval vessel approaching the strait, and claimed to have struck a US frigate in the area with two missiles.

Meanwhile, US Central Command on Monday said that US forces had redirected 50 commercial vessels amid the ongoing blockade.