President Donald Trump on Friday fired 18 inspectors general in the federal government, according to Hannibal “Mike” Ware, the head of the Council of the Inspectors General on Integrity and Efficiency who was also fired.

A senior White House official had previously confirmed to NBC News that at least a dozen inspectors general had been fired.

Among those terminated were inspectors general for the Defense Department, State Department, Health and Human Services Department and the Department of Labor. The move did not affect the inspectors general for the Justice Department or the Department of Homeland Security.

When asked why the inspectors general were fired, the White House official said the move was an effort by the president to let go of parts of the past Biden administration that don’t “align” with the new Trump administration.

“We’re cleaning house of what doesn’t work for us and going forward,” the official said.

The legal justification for the firings is murky, given that Congress strengthened protections for inspectors general from undue terminations when it amended the Inspector General Act in 2022.

The law requires a 30-day notification window between the White House informing Congress of its intent to fire an inspector general and that inspector general being removed from on-duty status. The White House must also provide substantive reasons for why the inspector general is being removed.

When asked whether the White House was concerned about the legality of the firings, given the required 30-day congressional notice for each inspector general, the official said a lot of these decisions happen with “legal counsel looking over them.” The official added that they were checking with the White House counsel’s office but didn’t think the administration had broken any laws.

The firings were first reported by The New York Times and The Washington Post.

Trump briefly touched on his firing decisions when addressing reporters Saturday evening on Air Force One.

“I did it because it’s a very common thing to do,” Trump said, despite the firings being highly unusual.

“Some people thought that some were unfair or were not doing the job. It’s a very standard thing to do, very much like the U.S. attorneys,” Trump reiterated.

However, inspectors general are typically considered to be independent figures within government agencies. They are tasked with conducting objective audits within their agency and they are expected to investigate allegations of waste, fraud and abuse of power within their departments.

In response to the firings, Ware sent a letter to his fellow inspectors general asking them to tell him if they were terminated and informing them that his council “is coordinating a response to the White House and wants to account for all the PAS IG’s that have received a notification.”

NBC News confirmed that Ware also sent a letter on behalf of CIGIE to the White House and to lawmakers on Capitol Hill about the firings.

In the letter, Ware addressed the legality of the firings, writing, “At this point, we do not believe the actions taken are legally sufficient to dismiss Presidentially Appointed, Senate Confirmed Inspectors General.”

Separately, Ware released a statement arguing that “removals inconsistent with the law are a significant threat to the actual and perceived independence of IGs.”

“IGs are not immune from removal,” he added. “However, the law must be followed to protect independent government oversight for America.”

Mark Lee Greenblatt, who was fired from his position as the Interior Department’s inspector general, said in an interview with NBC News that “the biggest concern I have just going forward is the politicization of inspector general positions.”

“The key question here is, who does the president appoint in the place of the IGs that he’s removed?” he asked, referring to inspectors general. “We’re so-called watch dogs inside the federal agency. So does he appoint true watch dogs, or does he appoint lap dogs?”

Greenblatt, who was appointed by Trump in 2019, also questioned whether inspectors general would be willing to investigate accusations against Trump allies.

“If a member of the Trump administration is accused of ethics, misconduct or some sort of criminal violation, will the IG be willing to investigate that in a fulsome and comprehensive manner? Will they be willing to come to findings, negative findings, about that Trump political appointee?” he asked. “That is the key question. That’s where the rubber meets the road.”

Sen. Chuck Grassley, R-Iowa, the chair of the Senate Judiciary Committee also noted that Trump’s decision did not abide by the firing process laid out in federal legislation. The senator led the push to protect inspectors general in the 2022 update to federal law.

“There may be good reason the IGs were fired. We need to know that if so. I’d like further explanation from President Trump. Regardless, the 30 day detailed notice of removal that the law demands was not provided to Congress,” Grassley told NBC News in a statement.

Trump’s move also drew swift condemnation from Democrats on Friday night and early Saturday.

In a speech on the Senate floor Saturday morning, Schumer called the firings a “chilling purge,” saying, “Yesterday, in the dark of night, President Trump fired at least 12 independent inspector generals at important federal agencies across the administration. This is a chilling purge, and it’s a preview of the lawless approach Donald Trump and his administration are taking far too often as he’s becoming president.”

Schumer added, “These dismissals are possibly in violation of federal law, which requires Congress to have 30 days notice of any intent to fire inspectors general.”

Danielle Brian, the executive director of the nonprofit and nonpartisan Project on Government Oversight, also raised concerns about the legality of the firings and Trump’s desire to get rid of “checks and balances.”

“It’s clear that this move demonstrates that this White House is really keen on removing checks and balances, and this was their one tool about rooting out waste and fraud and they shot themselves in the foot,” Brian told NBC News.

“I am still not convinced they will get away with this,” she added.

In a post on X, Sen. Elizabeth Warren, D-Mass., also called the firings a “purge” and added, “President Trump is dismantling checks on his power and paving the way for widespread corruption.”

In a statement, Rep. Gerry Connolly, D-Va., the top Democrat on the House Oversight Committee, also slammed Trump’s decision, calling it a “Friday night coup” and “an attack on transparency and accountability.”