President Donald Trump’s threat Friday to involve the military more deeply in the response to protests and looting in Minneapolis is unlikely to come to fruition, but he has the authority to deploy active-duty forces or National Guardsmen under his control, defense officials and national security experts said.

The threat came in two tweets from the White House after protests over the death of a handcuffed black man in police custody this week escalated into violence overnight. Trump tweeted as scenes of a police station and other buildings burning in Minneapolis aired on television amid calls for the officer’s arrest.

“These THUGS are dishonoring the memory of George Floyd, and I won’t let that happen,” Trump tweeted, referring to the man who died after an officer was shown on video pressing his knee into Floyd’s neck. “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. Thank you!”

The use of the word “thugs” has racist connotations, and Twitter labeled the message as a violation of the messaging service’s rules for “glorifying violence.” It was paired with another presidential tweet in which Trump said that he “can’t stand back & watch this happen to a great American City, Minneapolis.”

Trump warned that if the mayor of Minneapolis, Jacob Frey, doesn’t “get his act together and bring the City under control,” he will “send in the National Guard & get the job done right.”

The president did not acknowledge that Walz, a Democrat and retired commander in the National Guard, already had activated guardsmen to assist on Thursday.

Trump’s reaction immediately pulled the Pentagon deeper into a crisis that already has racial and political dynamics.

Trump’s tweets also had parallels to his comments about the southern border in 2018, when he suggested that if migrants threw rocks at U.S. troops dispatched there, American forces should treat the rocks as though they were rifles. After a backlash, Trump said the migrants would not be shot.

Walz’s activation of guardsmen to provide support to police in Minnesota follows similar actions by other governors amid unrest prompted by the death of black men at the hands of police, including in Ferguson, Missouri, in 2014, and in Baltimore in 2015.

In those cases, the guardsmen operated under state orders and did not participate in law enforcement in accordance with the federal Posse Comitatus Act, which limits the use of the military against American citizens under many circumstances.

But Trump could order federal troops to Minnesota under laws, such as the Insurrection Act, which allows presidents to deploy the military domestically during emergencies without the permission of a governor, said Stephen Vladeck, a professor at the University of Texas School of Law.

Such actions are rare but have occurred before, most recently in 1992 amid rioting in Los Angeles after the police beating of Rodney King was recorded on video. Then-President George H.W. Bush deployed 4,000 active-duty soldiers and Marines to complement thousands of National Guardsmen and police.

A defense official, speaking on the condition of anonymity to discuss internal deliberations, said he had seen no indication of imminent steps to federalize the National Guard under Trump’s control. While the president has the authority to take control of guardsmen, that would likely only occur if it was clear that authorities in Minnesota were unable to bring the situation under control, the official said.