Two top Democrats have told the Trump administration to preserve all records related to the Friday removal of the State Department’s inspector general, a late-night move that led House Speaker Nancy Pelosi (D-Calif.) to warn of an acceleration in a “dangerous pattern of retaliation” against federal watchdogs.

Rep. Eliot L. Engel (D-N.Y.) and Sen. Robert Menendez (D-N.J.) launched an investigation Saturday into the ouster of Steve Linick, the latest in a string of weekend removals of oversight officials who have clashed with the Trump administration. Engel, the chairman of the House Committee on Foreign Affairs, claimed Linick was fired after opening an investigation into Secretary of State Mike Pompeo and said the timing suggested “an unlawful act of retaliation.”

“President Trump’s unprecedented removal of Inspector General Linick is only his latest sacking of an inspector general, our government’s key independent watchdogs, from a federal agency,” he wrote with Menendez in an open letter.

Linick, a 2013 Obama appointee who has criticized department leadership for alleged retribution toward staffers, will be replaced by Stephen J. Akard, a State Department spokesperson confirmed Friday. The State Department did not explain Linick’s removal or respond to further questions, and the White House did not respond to inquiries.

A Democratic congressional aide said Linick was looking into Pompeo’s “misuse of a political appointee at the Department to perform personal tasks for himself and Mrs. Pompeo.”

President Trump said in a Friday letter to Pelosi that the inspector general no longer had his “fullest confidence” and would be removed in 30 days, the required period of advance notice to lawmakers.

Menendez, the ranking Democrat of the Senate Committee on Foreign Relations, called the firing “shameful” in a late Friday tweet. “Another late Friday night attack on independence, accountability, and career officials,” he wrote. “At this point, the President’s paralyzing fear of any oversight is undeniable.”

Menendez and Engel wrote to the White House, Department of State, and the State Department Office of Inspector General requesting officials turn over information to their committees by May 22.

The firing came weeks after Trump moved to replace Christi Grimm as principal deputy inspector general for the Department of Health and Human Services after Grimm’s office criticized the administration’s response to the coronavirus pandemic — detailing “severe shortages” of testing kits, delays in getting coronavirus results and “widespread shortages” of masks and other equipment at U.S. hospitals. Trump had lashed out publicly at Grimm.

Last month the president ousted intelligence community Inspector General Michael Atkinson, who handled the explosive whistleblower complaint that led to Trump’s impeachment. He also pushed out Glenn Fine, the chairman of the federal panel Congress created to oversee his administration’s management of the government’s $2 trillion coronavirus stimulus package.

The president’s critics responded with outrage Friday to the move against Linick. Rep. Adam B. Schiff (D-Calif.) slammed “another apparent act of retaliation and cover up” meant to “shield a loyal Cabinet secretary from oversight and accountability,” while Pelosi said in a statement that Linick was “punished for honorably performing his duty to protect the Constitution and our national security, as required by the law and by his oath.”

Pelosi expressed concern that the move came as the House passed coronavirus legislation that includes funding the State Department’s inspector general would oversee.

Sen. Chris Murphy (D-Conn.), also on Twitter, said “inspectors general are inconvenient, pesky brutes if your goal is turn the government into a cash cow for your friends, cronies and family.”

Linick has previously been critical of alleged misconduct by officials. An August report by the inspector general concluded that leadership of a leading department bureau mistreated and harassed staffers, accusing them of political disloyalty to the Trump administration and retaliating against them. Linick’s office also faulted actions by former Secretary of State Rex Tillerson.

His replacement, Akard, is a former Foreign Service officer who leads the State Department’s Office of Foreign Missions. Akard was nominated in 2017 to become director general of the Foreign Service but withdrew amid opposition.

John Hudson, Karen DeYoung and Lisa Rein contributed to this report.