Potus tells generals: 'Use American cities as training grounds'

Deep in the woods on Marine Corps Base Quantico, dozens of newly commissioned officers prepare for their assault on Mout Town, creeping through the trees in search of the best entry point, before the smoke grenades fly and gunfire rings out.

- Charlotte McDonald-Gibson

Under the close watch of military trainers, the marines move from building to building, putting into practice their basic training in an urban combat environment, which their instructors say will prepare them for the future of warfare anywhere in the world.

"Any sort of threat profile, violent or violent extremist, whatever the situation is, our duty is to make sure we have lieutenants that are ready to lead wherever we're assigned," said Lt Col Michael Breslin, the school's warfighting director.

During the visit by a small group of foreign journalists on 11 September, the marines were training for combat operations in a mocked-up city of empty shops, deserted homes and windowless municipal buildings, where the signs above the doors were in Dari (Afghan Persian).

But if Donald Trump gets his wish, troops could soon be put through their paces on the streets of Democratic-run US cities, which he painted as crime-ridden war zones teeming with enemy combatants in a speech to military top brass at the same Quantico base on Tuesday.

"San Francisco, Chicago, New York, Los Angeles, they're very unsafe. And we're going to straighten them out. This is going to be a major part for some of the people [here]. That's a war, a war from within," he said.