Sen. Elizabeth Warren, D-Mass., asked the Defense Department’s inspector general to investigate any military involvement in crowd dispersal tactics during the protests over the death of George Floyd.

In a letter to acting Inspector General Sean O’Donnell, Warren specifically mentioned reports that police used tear gas and rubber bullets on peaceful protesters Monday so President Trump could walk to St. John’s Episcopal Church in Lafayette Park – which was set on fire by rioters – for a photo op.

The Trump campaign denied reports that tear gas was used on the protesters. The statement said that, "We now know through the U.S. Park Police that neither they, nor any of their law enforcement partners, used tear gas to quell rising violence. We also know that police discovered stashes of weapons like glass bottles, baseball bats, and metal poles hidden nearby, which are indeed strange items to have on hand for a ‘peaceful’ protest."

Warren, like other Democrats, referred to the tactics as an “‘ambush’ of American citizens who were protesting the killing of [George] Floyd,” claiming it was done to allow Trump “to partake in a blatantly political photo opportunity.”

She also mentioned a call Trump made with several governors in which he said he wished there was an “occupying force” in major cities and in a speech to the nation this week he warned he would send “thousands and thousands” of soldiers to quell D.C. protests.

“The president further said he placed General Milley ‘in charge,’ despite the fact that as Chairman of the Joint Chiefs he has no operational authority and is not in the formal chain of command," Warren, who serves on the Senate Armed Services Committee, wrote.

PARK POLICE DEFENDS ACTIONS CLEARING PROTESTERS NEAR WHITE HOUSE, SAYS 'NO TEAR GAS WAS USED'

The United States Park Police denied any tear gas was used to clear away protesters. The USPP said they took the steps “to curtail the violence that was underway,” pushing back against claims that the protest was entirely peaceful.

“At approximately 6:33 pm, violent protestors on H Street NW began throwing projectiles including bricks, frozen water bottles and caustic liquids,” the USPP said in a statement. “The protestors also climbed onto a historic building at the north end of Lafayette Park that was destroyed by arson days prior. Intelligence had revealed calls for violence against the police, and officers found caches of glass bottles, baseball bats and metal poles hidden along the street.”

Still, the Park Police acknowledged using smoke canisters and pepper balls on the protesters.

“As many of the protestors became more combative, continued to throw projectiles, and attempted to grab officers’ weapons, officers then employed the use of smoke canisters and pepper balls when protestors did scatter from the area," the statement said.

White House spokesperson Judd Deere said in a statement: "The perimeter was expanded to help enforce the 7:00 pm curfew in the same area where rioters attempted to burn down one of our nation’s most historic churches the night before. Protesters were given three warnings by the U.S. Park Police."

Several reporters in the crowd said they didn’t hear the warnings.

Defense Secretary Mark Esper, who participated in the photo op, said he wasn’t given advance notice by the president, according to The Hill.

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Trump walked from the White House to the church after it was reported he was ushered into a White House bunker Friday as protesters pushed at police barricades and threw rocks at police.

fox News' Andrew O'Reilly contributed to this report.