President Trump stoked the already burning fires of Minneapolis as he warned protesters outraged at the death of George Floyd by tweeting, ’When the looting starts, the shooting starts’.

He labelled the angry crowds ’thugs’, blasted the mayor Jacob Frey for losing control of  the city and threatened to call in the National Guard, saying ’Any difficulty and we will assume control’.

And in a move likely to anger the President in his spat with social media giants even more, Twitter hid his post with the message: “This Tweet violated the Twitter Rules about glorifying violence. However, Twitter has determined that it may be in the public’s interest for the Tweet to remain accessible,” with a link inviting readers to ’Learn more’.

On Thursday, the third night of demonstrations, protesters targeted the Police Department's 3rd Precinct, the base for four officers involved in the incident who were fired after Floyd's death. 

He died on Monday, after disturbing scenes captured on video showed an officer kneeling on his neck for a protracted period while arresting him.

The police station was one of several burning buildings torched in Minneapolis.

Police cleared the building shortly after 10pm when demonstrators forcibly entered and ’ignited several fires’, department spokesman John Elder said.

The Minnesota Guard said on Twitter that 500 soldiers have been activated for duty in the Twin Cities. "Our mission is to protect life, preserve property and the right to peacefully demonstrate," it said.

Protesters are demanding that the officers involved in Floyd's arrest be charged. Looting and fires have been widespread in the area where Floyd died Monday.

"These THUGS are dishonoring the memory of George Floyd, and I won’t let that happen," Trump tweeted.

Frey responded early Friday, saying: "Weakness is pointing your finger at somebody else during a time of crisis. Donald Trump knows nothing about the strength of Minneapolis."

Video of Floyd’s detainment sparked nationwide outrage as it showed the man pleading with officers to let him stand because he was struggling to breathe.

"Please, please, please, I can't breathe," Floyd said in the video. "My stomach hurts. My neck hurts. Please, please. I can't breathe."

The officer kept his knee on his neck for about eight minutes. Medics worked on an unresponsive Floyd in an ambulance, but could not find a pulse after several checks and administering at least one shock to him, according to a report from the Minneapolis Fire Department.

US Attorney for the District of Minnesota Erica MacDonald said it was imperative the community understood how seriously the department was taking the investigation for Floyd's death.

“It breaks my heart to see what is happening in our streets in Minneapolis and St Paul and in some of our suburbs,” MacDonald said. “And I am pleading, I am pleading with individuals to stay calm and to let us conduct this investigation.”