President Donald Trump vowed Monday to order a military crackdown on once-in-a-generation violent protests gripping the United States, saying he was sending thousands of troops onto the streets of the capital and threatening to deploy soldiers to states unable to regain control.

The dramatic escalation came a week after the death in Minneapolis of George Floyd, an unarmed black man who was killed when a white police officer knelt on his neck, leading to the worst civil unrest in decades in New York, Los Angeles and dozens of other American cities.

After being criticised for his silence on the worsening crisis, Trump struck a martial tone in a nationwide address from the White House garden, as police fired tear gas on peaceful protesters outside the fence.

“I am dispatching thousands and thousands of heavily armed soldiers, military personnel and law enforcement officers to stop the rioting, looting, vandalism, assaults and the wanton destruction of property,” Trump said.

He slammed the previous night’s unrest in Washington as a “total disgrace” and called on governors to “dominate the streets.”