Senate Majority Leader Mitch McConnell (R-Ky.) on Tuesday defended President Trump’s removal of Steve Linick as the State Department’s inspector general, arguing that the president was well within his rights.

“Look. He is certainly within his authority,” McConnell told reporters at the Capitol when asked about Trump’s firing of Linick. “He gets to hire and fire under the Constitution all people in the executive branch.”

Trump terminated Linick late Friday night and replaced him with Stephen J. Akard, a trusted ally of Vice President Pence and the diplomat who directs the Office of Foreign Missions.

The reason for Linick’s removal remains unclear. A congressional official familiar with the matter told The Washington Post on Sunday that Linick had been investigating allegations that a staffer for Pompeo was performing domestic errands and chores such as handling dry cleaning, walking the family dog and making restaurant reservations.

But House Foreign Affairs Committee Chairman Eliot L. Engel (D-N.Y.) cited what he said was another possible reason, saying Linick was investigating an emergency declaration Trump made last year to approve an arms sale to Saudi Arabia, a decision Secretary of State Mike Pompeo approved.

Trump initially said that he had fired Linick because he had lost confidence in him. But on Monday, he told reporters at the White House that Pompeo had asked him to fire Linick.

“I don’t know the gentleman,” Trump said of Linick. “I was happy to do it. Mike requested that I do it.”

Democrats have launched an investigation into Trump’s move and have sharply criticized the president for what they say is a pattern of removing inspectors general throughout his administration in an effort to avoid accountability.

Senate Minority Leader Charles E. Schumer (D-N.Y.) on Tuesday renewed his criticism of the president’s move.

“I would say this, Trump has fired four inspectors general in three months,” Schumer told reporters at the Capitol, adding that when Trump “hears the truth and it doesn’t square with what he wants to hear, instead of adapting to the truth, he fires the truth teller.”

Trump’s actions, he said, “will hurt us across the board.”

Most Republicans, meanwhile, have remained silent about the firing. But on Monday, Sen. Charles E. Grassley (R-Iowa) called on Trump to detail the reasons behind his decision, arguing that Trump’s claim that he lost confidence in Linick “is not sufficient” to fulfill the requirements of the 2008 Inspector General Reform Act.

“Inspectors General help ensure transparency and accountability, both of which are critical for taxpayers to have confidence in their government,” Grassley said in a letter to Trump. “They should be free from partisan political interference, from either the Executive or Legislative branch.”

Colby Itkowitz contributed to this report.