U.S. President Donald Trump said on Saturday that states and cities must get “much tougher” on anti-police protests or the federal government will step in, including by using the military and making arrests. “Liberal Governors and Mayors must get MUCH tougher or the Federal Government will step in and do what has to be done, and that includes using the unlimited power of our Military and many arrests,” he said in a tweet.

Some residents are working on picking up the pieces in parts of Minneapolis Saturday (May 30) after four nights of sometimes violent protests that have spread to other U.S. cities following the killing of a black man by a white Minneapolis police officer who knelt on his neck.

Demonstrations broke out for a fourth night despite prosecutors announcing on Friday that the policeman filmed kneeling on George Floyd’s neck, Derek Chauvin, had been arrested on third-degree murder and manslaughter charges.

One Minneapolis resident joining dozens of others in the clean up told Reuters, “Everyone is coming out as a community and still trying to make sure that we are healing together.”

The full Minnesota National Guard was activated for the first time since World War Two. Minnesota Governor Tim Walz said the deployment was needed because outsiders were using the demonstrations over the death of George Floyd to spread chaos, and that he expected Saturday night’s protests to be the fiercest so far.

From Minneapolis to New York City, Atlanta and Washington, protesters clashed with police late on Friday in a rising tide of anger over the treatment of minorities by law enforcement.

The video of Floyd’s death, filmed by a bystander, showed the 46-year-old repeatedly pleading with the officers and telling them he could not breathe.