United States President Donald Trump on Thursday called those involved in the protests against the death of an African American man in police custody “thugs”. George Floyd died after a white Minneapolis police officer knelt on his neck as he lay on the ground during an arrest on Monday.

Videos captured by the bystanders at the scene showed Floyd shouting “I cannot breathe” and “don’t kill me”. Floyd, a 46-year-old restaurant worker, was seen gasping for breath after the police officer detained him for allegedly using a counterfeit $20 bill in a purchase.

Demonstrators across the country continued their protests for the third night on Thursday. Outside Minneapolis police precinct station, protestors clashed repeatedly with the police in riot gear, AP reported. They also set the police station on fire. A police spokesperson said the staff had evacuated the station “in the interest of the safety of our personnel” shortly after 10 pm. The third precinct covers the area of south Minneapolis where Floyd was arrested. A car and at least two other buildings in the vicinity were also set ablaze during the demonstrations.

Late Thursday, Trump castigated the “total lack of leadership” in Minneapolis. “Either the very weak radical left Mayor, Jacob Frey, get his act together and bring the city under control, or I will send in the National Guard and get the job done right,” he tweeted. “These thugs are dishonoring the memory of George Floyd, and I won’t let that happen. Just spoke to Governor Tim Walz and told him that the military is with him all the way. Any difficulty and we will assume control but, when the looting starts, the shooting starts.”

Minnesota Governor Tim Walz earlier in the day activated the National Guard at the Minneapolis mayor’s request. The Guard tweeted minutes after the station burned that it had activated more than 500 soldiers across the metro area. “Our mission is to protect life, preserve property and the right to peacefully demonstrate,” it added. “A key objective is to ensure fire departments are able to respond to calls.”

However, it is not clear when and where the Guard was being deployed. The angry protestors also reportedly carried mannequins from a looted Target store and threw them onto a burning car. In Los Angeles and Denver, hundreds of demonstrators blocked traffic in both cities. Elsewhere in Minneapolis, thousands marched through the streets calling for justice after Floyd’s death.

Four city police officers involved in the incident, including the one pressing his knee into Floyd’s neck, were fired from their jobs on Tuesday. Meanwhile, officials overseeing investigations from the US Justice Department, Federal Bureau of Investigation, Minnesota Bureau of Criminal Apprehension and prosecutors appealed for calm at a press conference. “Give us the time to do this right, and we will bring you justice,” County Attorney Mike Freeman told reporters. He also accepted the police officers conduct in the video was “horrible”, adding that his job his, however, to prove that he violated a criminal statute.

Here are some visuals from the protest in the US: