Three days after the U.S. Park Police claimed that tear gas was never used on protesters outside the White House, the organization’s spokesman acknowledged that the chemical agents shot into the largely peaceful crowd have similar painful effects.

A spokesman for the Park Police said in an interview with Vox that his agency regretted using the term “tear gas,” noting that officers threw pepper balls containing an irritant powder and chemical agents that are designed to produce tears. Their use causes people to experience difficulty breathing and burning sensations on the skin.

“The point is, we admitted to using what we used,” Sgt. Eduardo Delgado, the spokesman, told Vox. “I think the term ‘tear gas’ doesn’t even matter anymore. It was a mistake on our part for using ‘tear gas’ because we just assumed people would think CS or CN,” two common forms of tear gas.

“I’m not saying it’s not a tear gas, but I’m just saying we use a pepper ball that shoots a powder,” Delgado added.

But two hours later, after The Washington Post contacted the Park Police and the White House for comment, acting Park Police chief Gregory T. Monahan walked back that acknowledgment.

In a statement from Monahan emailed by Delgado, the acting chief repeated that “United States Park Police officers and other assisting law enforcement partners did not use tear gas or OC Skat Shells to close the area at Lafayette Square in response to violent protestors.” Delgado declined to comment further.

The Park Police’s initial denial — echoed by the White House and President Trump’s reelection campaign — became a national controversy amid the outrage that followed the forcible removal of protesters from streets near the White House on Monday evening.

Reporters on the scene when Park Police and other officers wielding batons and shields shoved demonstrators — who were protesting the death of George Floyd while in police custody in Minneapolis — out of Lafayette Square said they personally experienced noxious fumes descending on the crowd, and suffered the eye irritation and difficulty breathing.

But the president and his allies used the Park Police’s denial to attack news organizations, claiming that irresponsible media outlets exaggerated the methods officers had used on protesters to make the government response appear more heavy handed.

“Every news organization which reported the tear gas lie should immediately correct or retract its erroneous reporting,” Tim Murtaugh, a spokesman for the Trump campaign, said in a statement Tuesday.

On Wednesday, the White House repeated that claim. “No tear gas was used, and no rubber bullets were used,” White House press secretary Kayleigh McEnany told reporters.

On Friday, White House spokesman Judd Deere declined to comment on the Park Police spokesman’s admission that the agency made a “mistake” or whether the White House had asked the acting chief to issue a statement.

But he tweeted the Vox story with the word “FALSE!” and a link to the latest statement from the acting Park Police chief.

Murtaugh said: “What the campaign said is completely consistent with what the Park Police is saying. There was no ‘tear gas’ used. The media is trying to widen the definition of tear gas to make their own original reporting seem accurate.”

Reporters found evidence of tear gas and rubber pellets littering the streets in the aftermath of Monday’s protest.

At least one spent canister reporters recovered from the streets outside the park Monday was labeled “Skat Shell OC.” The OC stands for oleoresin capsicum, an oily substance derived from chile peppers that is often used in topical ointments and “heat” creams for arthritis relief and muscle pain. When it gets into the eyes, noses and lungs, however, it triggers searing pain, coughing, sneezing and mucus secretion.

Reporters for WUSA-TV also collected a canister labeled “Speed-Heat CS” — exactly the kind of tear gas that Delgado said the agency did not use.

And a reporter for The Washington Post found a silver canister Monday labeled “Sting-Ball 60CAL Rubber Pellet.”

No agency has acknowledged shooting rubber pellets into the crowd, although witnesses reported being hit with such projectiles.

As outrage built Tuesday morning about the use of force against the demonstrators, Delgado told The Post in an interview that the media had erroneously reported the use of tear gas.

“Everybody got it wrong,” he said. “There was no tear gas. We used smoke canisters.”

Later that day, after the Trump campaign had released its statement that called the use of tear gas a lie, Monahan issued his own statement.

He began by describing violence by protesters from Friday through Monday, saying that 51 of his officers were injured. Monahan said the Park Police at Lafayette Square used force because “many of the protesters became more combative, continued to throw projectiles, and attempted to grab officers’ weapons.” (Witnesses reported that although some water bottles were thrown, the crowd was largely calm.)

“Officers then employed the use of smoke canisters and pepper balls,” he said, adding that tear gas was not used.

It was a distinction with very little difference.

According to the Centers for Disease Control and Prevention, riot-control agents are “chemical compounds that temporarily make people unable to function by causing irritation to the eyes, mouth, throat, lungs, and skin.”

Several compounds fall under this category, according to the CDC. Among others, they include chloroacetophenone (CN), more commonly referred to as mace or pepper spray. Such compounds are all typically referred to as “tear gas” because their most prominent effect is to irritate mucus membranes, including the eyes, which secrete tears as a protective response.

Hannah Natanson, Abigail Hauslohner, William Wan and Nick Miroff contributed to this report.