Donald Trump is about to address an extraordinary gathering of hundreds of US generals and admirals who were summoned from around the world.

Pete Hegseth, the defence secretary, called the meeting last week, without providing an explanation.

Speaking to reporters before the event, the US president warned of a possible overhaul in the military and upcoming dismissals. “If I don’t like somebody I am gonna fire them on the spot,” he said.

Military officials and historians say the event is unprecedented in size and scope.

Speaking ahead of Mr Trump at a marine base in Virginia, Mr Hegseth gushed about “warrior ethos,” one of his favourite subjects, and vowed that the military would have “no more climate change worship, no more division, distraction or gender delusions.

The meeting comes after eight months of fast changes at the Pentagon, including firing the chairman of the Joint Chiefs of Staff and the Navy’s top admiral, banning books from academy libraries and lethal strikes on suspected drug boats off Venezuela.

That has led to speculation that the gathering could go far beyond the morale-boosting exercise described by Mr Trump to include discussions about reductions in senior officers’ ranks and a revamp of defence priorities.