Defense Secretary Mark Esper has ordered military police active-duty troops from Fort Bragg and Fort Drum and a ready battalion from the 82nd Airborne to stage in the Washington, D.C. area at Maryland's Andrews Air Force Base and Virginia's Fort Belvoir, a senior U.S. defense official told Fox News.

This comes after President Trump said he may use the military to help quell violence and looting taking place in the nation's capital and other cities across the country. Trump would have to invoke the Insurrection Act in order to take such measures, as military involvement with domestic law enforcement is generally prohibited.

WHAT POWERS DOES THE PRESIDENT HAVE TO USE MILITARY TO QUELL DOMESTIC UNREST?

In remarks Monday evening, Trump said he was "an ally of all peaceful protesters," but took a hard-line stance against those who choose violence.

"We will end it now," Trump said. The president urged governors to seek the aid of the National Guard, warning that if states and cities fail to protect their residents, he will send the military to do it instead.

During his remarks, however, Trump stopped short of invoking the Insurrection Act. Senior administration officials told Fox News Tuesday morning that it is being “seriously considered,” but only as a “last resort.” The White House hopes the threat of invoking it will be enough to push mayors and governors across the country to crack down on protesters and “dominate the streets.”

Meanwhile, a senior administration official told Fox News that contrary to what Trump said in a phone call with governors, Chairman of the Joint Chiefs of Staff Gen. Mark Milley is not in charge of the response to protests.

“General Milley’s role has not changed," the official said. "He is the senior military adviser to the President. He is not issuing orders to the governors or overseeing National Guard troops in Washington, D.C."

TRUMP VOWS TO MOBILIZE FEDERAL RESOURCES IN ADDRESS TO NATION, MAKES SURPRISE TRIP TO CHURCH THAT CAUGHT FIRE

Former Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey took issue on Twitter with the term “battle space” that had been used by Esper, and language on the president's call with governors to “get control of the battle space,” suggesting the U.S. military should be used to stamp out protests.

Former Special Operations Commander General Tony Thomas, a well-respected Army Ranger also objected to this language.

"The 'battle space' of America??? Not what America needs to hear...ever, unless we are invaded by an adversary or experience a constitutional failure...ie a Civil War," Thomas tweeted.

Many top Pentagon leaders are opposed to such drastic measures, and some current and former officials have expressed frustration that the U.S. military is being used as a “prop“ by the president in a standoff with violent protesters who have taken to the streets in the aftermath of the death of George Floyd, the Minneapolis man who died in police custody May 25 after an officer kneeled on his neck for more than eight minutes.

Meanwhile, the National Guard has been activated in more than half the country. A National Guard statement on Tuesday said governors in 28 states and D.C. have activated thousands of Guard members to help local law enforcement.

Some other governors have rejected the president's offers to deploy the National Guard and criticized his suggestion to involve armed forces.

"I say thank you but no thank you," New York Gov. Andrew Cuomo said on CNN Monday in response to Trump. So far Cuomo has not deployed the state's National Guard to New York City, although he said earlier Monday the state had 13,000 troops that "we can use at any moment."

Illinois Gov. J.B. Pritzker also pushed back against Trump's suggestion of using the military.

"I reject the notion that the federal government can send troops into the state of Illinois," Pritzker told CNN.

TRUMP UNLOADS ON GOVERNORS OVER PROTEST RESPONSE, CALLS THEM 'WEAK' 

D.C. Mayor Muriel Bowser criticized Trump's use of federal police to clear an area in D.C.'s Lafayette Square Monday evening.

"I imposed a curfew at 7pm. A full 25 minutes before the curfew & w/o provocation, federal police used munitions on peaceful protestors in front of the White House, an act that will make the job of DCPoliceDept  officers more difficult. Shameful!" Bowser tweeted Monday night.

Also Monday night, Arlington County withdrew police officers from D.C. who had been present as part of an agreement with the district that may now be in jeopardy.

CLICK HERE TO GET THE FOX NEWS APP

"The County is re-evaluating the agreements that allowed our officers to be put in a compromising position that endangered their health and safety, and that of the people around them, for a purpose not worthy of our mutual aid obligations," the county said in a news release.

Fox News' Kristin Fisher and The Associated Press contributed to this report.