CNN  — 

A spokesperson for the US Park Police said Friday afternoon that the department had made a mistake by denying use of tear gas to clear peaceful protesters from a public park outside the White House earlier this week. Not long after, the department’s acting chief once again denied using tear gas.

Sgt. Eduardo Delgado, a spokesperson for the Park Police, told CNN on Friday he now realized the department could have called the pepper balls it used “tear gas,” reiterating what he had first told Vox, that it was a “mistake” to say the force hadn’t used tear gas on Monday.

“The point is we admitted to using what we used,” Delgado first 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.”

CS and CN are two substances widely referred to as tear gas.

The semantics debate over what to call the particular chemical irritants police used to disperse protesters began when the department released a statement on Tuesday saying that it “did not use tear gas” to clear dozens of protesters from Lafayette Square on Monday evening in a chaotic scene of gas and force. The protesters were cleared so that President Donald Trump could walk to the nearby St. John’s Episcopal Church for a photo op. Trump and conservatives cited the Park Police’s statement in attacks on media coverage of the event – even though the police acknowledged using chemical irritants.

Delgado said on Friday that the force still stood behind its statement from Tuesday, which explained that it had used smoke bombs and pepper balls to clear the crowd. The force has never said it used CS gas, a chemical irritant that the Park Police claimed they commonly refer to as tear gas, and stands by that still.

However, pepper balls are also a chemical irritant that is colloquially referred to as tear gas. The US Centers for Disease Control and Prevention notes that tear gas is often used to describe different substances that are employed for crowd control.

“Riot control agents (sometimes referred to as ‘tear gas’) are chemical compounds that temporarily make people unable to function by causing irritation to the eyes, mouth, throat, lungs, and skin,” as defined by the CDC.

But not long after Delgado spoke to Vox acknowledging a mistake, US Park Police acting Chief Gregory T. Monahan doubled down on denying tear gas had been used.

“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 Park in response to violent protestors,” Monahan said in a statement.

The President’s campaign on blamed the media for the semantics debate.

Tim Murtaugh, director of communications for Trump’s campaign, in an emailed statement to CNN reiterated that tear gas had not been used and blamed the media for the discrepancy.

“The media is trying to widen the definition of tear gas to make their own original reporting seem accurate,” said Murtaugh.

The White House did not respond to a request for comment.

The incident is under investigation by multiple House committees. Four Democratic chairmen wrote to Attorney General William Barr, Defense Secretary Mark Esper, Interior Secretary David Bernhardt and acting Homeland Security Secretary Chad Wolf on Wednesday seeking information and a briefing by next week about who gave the order to clear the park, which federal agencies were involved and what measures and authorizations were used.

Bernhardt responded to one of those chairmen – House Natural Resources Chairman Raul Grijalva of Arizona – in a letter sent Friday. In that letter, Bernhardt also denied that tear gas had been used, despite Delgado’s acknowledgment that saying so was a mistake.

“On the evening of June 1, 2020 crowds gathered near the White House complex and once again began assaulting law enforcement with projectiles while threatening to storm the secured areas,” Bernhardt’s letter stated.

“While standard equipment, including shields, batons and pepper balls, where (sic) used to accomplish this, no tear gas was used by USPP … contrary to widely and erroneously reported assertions.”

While the Park Police and Secret Service have both denied employing CS gas while clearing protesters from the square, members of the media have reported their eyes and throats being irritated and television cameras recorded multiple protesters pouring milk into their eyes, a common solution for tear gas exposure.

A WUSA reporter has said he found spent CS gas canisters near Lafayette Park, but Delgado said they are not from the Park Police because such canisters aren’t carried among the force.

CNN’s Lauren Fox contributed to this report.