WASHINGTON — President Donald Trump threatened Monday evening to deploy the United States military unless states quickly halted the violent protests that have convulsed cities from coast to coast.

His remarks from the Rose Garden came hours after the brother of George Floyd — the black man who died May 25 following a confrontation with Minneapolis police — pleaded for peace, saying destruction is “not going to bring my brother back at all.”

Trump urged the nation’s governors to get tougher with violent protesters and to deploy the National Guard.

“We have the greatest country in the world,” Trump declared. “We’re going to keep it safe.”

Speaking from the Rose Garden, the president said he is an ally of peaceful protesters, but he stressed that “I am your president of law and order.”

He held a Bible and stood with several of his Cabinet members as the cameras clicked.

Trump recommended that governors throughout the country deploy the National Guard in sufficient numbers to “dominate the streets.”

If governors fail to take action, Trump said, he will deploy the United States military and “quickly solve the problem for them.”

Trump said he would mobilize “thousands and thousands” of soldiers to keep the peace if governors did not use the National Guard to shut down the protests.

Following his comments, Trump visited a 200-year-old church near the White House that was set on fire as demonstrators clashed with police over the weekend.

Demonstrators were cleared so Trump could walk across Lafayette Park to St. John’s Episcopal Church, known as “The Church of the Presidents,” which suffered fire damage in a protest.

Hours earlier in Minneapolis, Floyd’s brother, Terrence, made an emotional plea for peace at the site where Floyd was pinned to the pavement by an officer who put his knee on the handcuffed black man’s neck until he stopped breathing.

“Let’s switch it up, y’all. Let’s switch it up. Do this peacefully, please,” Terrence Floyd said.

The competing messages came as the U.S. braced for another round of violence at a time when the country is already buckling because of the coronavirus outbreak and the Depression-level unemployment it has caused.

Under the Civil War-era Posse Comitatus Act, federal troops are prohibited from performing domestic law enforcement actions such as making arrests, seizing property or searching people. In extreme cases, however, the president can invoke the Insurrection Act, also from the Civil War, which allows the use of active-duty or National Guard troops for law enforcement.

The National Guard presence in Washington was much more overt Monday than the day before. Beige hummers blocked several downtown intersections.

In a teleconference earlier, the president urged the governors to deploy the National Guard, which he credited for helping calm the situation Sunday night in Minneapolis. He demanded that similarly tough measures be taken in cities that also experienced violence, including New York, Philadelphia and Los Angeles.

“You’ve got to arrest people, you have to track people, you have to put them in jail for 10 years and you’ll never see this stuff again,” Trump said. “We’re doing it in Washington, D.C. We’re going to do something that people haven’t seen before.”