An Army National Guard officer who witnessed protesters forcibly removed from Lafayette Square last month is contradicting claims by the attorney general and the Trump administration that they did not speed up the clearing to make way for the president’s photo opportunity minutes later.

A new statement by Adam D. DeMarco, an Iraq veteran who now serves as a major in the D.C. National Guard, also casts doubt on the claims by acting Park Police Chief Gregory Monahan that violence by protesters spurred Park Police to clear the area at that time with unusually aggressive tactics. DeMarco said that “demonstrators were behaving peacefully” and that tear gas was deployed in an “excessive use of force.”

DeMarco backs up law enforcement officials who told The Washington Post they believed the clearing operation would happen after the 7 p.m. curfew that night — but it was dramatically accelerated after Attorney General William P. Barr and others appeared in the park around 6 p.m. Monahan has said the operation was conducted so that a fence might be erected around the park. DeMarco said the fencing materials did not arrive until 9 p.m. — hours after Barr told the Park Police to expand the perimeter -- and the fence wasn’t built until later that night.

DeMarco’s account of events also reveals for the first time the details of the visit that Gen. Mark A. Milley, chairman of the Joint Chiefs of Staff, made to Lafayette Square just before the move on protesters — and the warning he gave his troops.

Milley, who had arrived in the park with Barr about 30 minutes before the clearing, warned DeMarco to keep officers from going overboard. “General Milley told me to ensure that National Guard personnel remained calm, adding that we were there to respect the demonstrators’ First Amendment rights,” DeMarco said.

Milley has since apologized for his presence in Lafayette Square, saying, “I should not have been there. My presence in that moment, and in that environment, created the perception of the military involved in domestic politics.”

DeMarco is scheduled to testify Tuesday before the House Natural Resources Committee, which is investigating the government’s actions in clearing protesters away from Lafayette Square with projectiles, gas, smoke and mounted police, including an apparent assault on Australian journalists by two Park Police officers. His statement was posted Monday on the committee’s website.

Monahan also is scheduled to testify. In a statement posted Monday evening by the committee, Monahan asserts that violence beginning May 29 outside the White House led to the decision to expand the perimeter with fencing that protesters could not scale. “The unprecedented and sustained nature of the violence and destruction associated with some of the activities in Lafayette Park and surrounding park areas immediate and adjacent to the White House required de-escalation,” and that the decision was made late on May 30, the chief’s statement says.

Monahan said, “Once the fencing arrived, an on-the-ground assessment of the violence and danger presented by the crowd led to the clearing of the Park and the installation of the fence.” That conflicts with DeMarco’s claim that the fencing didn’t arrive until later that night.

“The hearing comes at an interesting time, during the protests in Portland and Seattle,” said Rep. Raul Grijalva (D-Ariz.), chair of the natural resources committee, “and the presence of both police and ICE in those areas. What happened at Lafayette Square was kind of a precursor to the escalations this administration is using, the using of federal law enforcement, the contemplation of use of the military in these communities.”

The Trump administration has said the clearing operation was planned in advance, and Justice Department spokeswoman Kerri Kupec previously said, “No one voiced disagreement with that plan.” The White House has not commented on the timing of the operation, which started about 30 minutes before a 7 p.m. curfew.

As police were clearing the area around Lafayette Square, Trump began a short speech at the White House, and some of the small explosions from the park could be heard in the background. Trump then walked with an entourage to the park, which is adjacent to the White House, and stood in front of St. John’s Episcopal Church. He was photographed holding a Bible, did not make any remarks, and then walked back to the White House.

Barr said in a news conference on June 4 that he made the decision to expand the perimeter north of Lafayette Square, from H Street to I Street.

“There was no correlation between our tactical plan of moving the perimeter out by one block and the president’s going over to the church,” Barr said.

The Justice Department did not respond to a request for comment Monday.

Laws and court rulings require police to provide demonstrators with repeated, clear warnings of officers’ intentions and then adequate time and avenues for protesters to disperse peacefully, but DeMarco said the warnings given on June 1 almost certainly couldn’t be heard by the crowd. If the street was cleared to accommodate Trump, rules of engagement for the Secret Service also may have been broken.

After the death of George Floyd in Minneapolis police custody on May 25, demonstrations began at Lafayette Square and elsewhere in the nation’s capital. On the night of May 31, projectiles and fireworks were launched toward Park Police officers and National Guard soldiers stationed in the park, and fires were set both at the park and in adjacent St. John’s Church. The Park Police have said 51 officers were injured in the days immediately after the protests began.

The next day, a number of agencies gathered to defend the park, including the Park Police, Secret Service, the D.C. National Guard and Arlington County police. A 2 p.m. meeting was held at an FBI command center with the heads of the agencies, and Barr told CBS News that a decision to expand the perimeter around the park “was communicated to all the police agencies.”

But no specific time or plan of action was discussed, both D.C. Police Chief Peter Newsham and National Guard chief Gen. Joseph L. Lengyel told The Post last month. DeMarco’s testimony corroborates that version. A curfew was set for 7 p.m., “so I was not expecting any clearing operation to commence before then,” DeMarco said.

But at 6:05 p.m., DeMarco said, Barr and Milley entered the park. DeMarco said he briefed the Army general, who told him to respect the demonstrators’ rights. Grijalva said it seemed that Milley knew something was planned, “there’s a tinderbox here and he wants his people to respect the rights of the protesters.”

Milley has testified he had no prior knowledge of the forcible clearing of Lafayette Square. A Defense Department official said Monday that Milley was simply surveying the situation in the park because of the president’s wish to use military troops to quell protests, and Milley was satisfied law enforcement could handle the protest.

“We had seen a lot of violence in protests over the previous days," the official said. "He was just reminding forces on the ground that we were there to support law enforcement and to stay calm in the face of uncertainty.”

At 6:20 p.m., DeMarco said, the Park Police issued three warning announcements to the protesters. But he said the warnings were made using a hand-held megaphone at the base of the Andrew Jackson statue, 50 yards from the protesters. DeMarco said he stood 20 yards from the protesters, “the announcements were barely audible and I saw no indication that the demonstrators were cognizant of the warnings to disperse.”

The operation to clear the protesters began at 6:30 p.m., DeMarco said. The National Guard did not participate in the direct push, but was used to follow the officers who dispersed the protesters and establish the new perimeter, DeMarco said. The Guard members were not armed.

As the federal and local police waded into the protesters, DeMarco said he saw smoke being used and that he was told by a Park Police officer it was “stage smoke,” not tear gas. But DeMarco said, “I could feel irritation in my eyes and nose, and based on my previous exposure to tear gas in my training at West Point and later in my Army training, I recognized that irritation as effects consistent with CS or ‘tear gas.’" He said he found spent tear gas canisters on the street later.

The Park Police have adamantly denied using tear gas, instead saying they shot balls with pepper spray irritant in them. The Secret Service have not commented on whether it fired tear gas.

DeMarco said that as he followed the Park Police down H Street, he saw “unidentified law enforcement personnel behind our National Guardsmen using ‘paintball-like’ weapons to discharge what I later learned to be ‘pepper balls’ into the crowd, as demonstrators continued to retreat.

The protesters were pushed a block away from Lafayette Square. At 7:05 p.m.,DeMarco said he watched Trump walking onto H Street, where he would have his picture taken holding up a Bible. “The president’s arrival was a complete surprise,” DeMarco said, “as we had not been briefed that he would enter our sector.”

“As for the new security barrier,” DeMarco continued, “whose installation was the stated purpose of the clearing operation, the materials to erect it did not arrive on the scene until around 9 p.m., and it was not completed until later that night.” This required the local and federal police to maintain a human barricade for hours until the fence was built.

DeMarco, 34, is a U.S. Military Academy graduate and a veteran of three overseas deployments, including a combat tour in Iraq. In 2018, he ran in the Democratic primary for Congress against incumbent Rep. John Sarbanes, and was strongly critical of Trump. He now works as an associate for Booz Allen Hamilton at the Defense Intelligence Agency, according to his LinkedIn profile.

DeMarco said he was coming forward “to help ensure that there is a fair factual record of what happened at Lafayette Square, based on what I saw and experienced first-hand.” He said that, having served in a combat zone and having experience in assessing threats, “at no time did I feel threatened by the protesters or assess them to be violent … From my observation, these demonstrators — our fellow American citizens — were engaged in the peaceful expression of their First Amendment rights. Yet they were subjected to an unprovoked escalation and excessive use of force.”

Grijalva said DeMarco’s testimony showed “the discomfort the military has with policing against the American citizen. This was a political stunt at the expense of the protesters and at the expense of the reputations of the National Guard and the police.”

An earlier version of this article incorrectly referred to DeMarco as a commander rather than an officer.