Attorney General Jeff Sessions over the weekend asked 46 U.S. Attorneys General who served under the Obama administration to immediately tender their resignations, according to the Department of Justice.

The call for resignations is not unusual for a new administration, but many attorneys general were caught off-guard by the abruptness of the request, having no indication that they were going to be let go.

Preet Bharara was among those high-profile federal prosecutors to get the axe—and just months after President Donald Trump asked Bharara to stay on as U.S. Attorney for the Southern District of New York. “I did not resign,” Bharara tweeted Saturday. “Moments ago I was fired.”

Several other U.S. attorneys around the country did announce their resignations over the weekend, including New Jersey and Rhode Island.

In response to the move, many U.S. lawmakers expressed concern over the sudden firings. “Under previous administrations, orderly transitions allowed U.S. attorneys to leave gradually as their replacements were chosen,” Ranking Member of the Senate Judiciary Committee Dianne Feinstein said in a statement. “This was done to protect the independence of our prosecutors and avoid disrupting ongoing federal cases.”

“In January, I met with Vice President [Mike] Pence and White House Counsel Donald McGahn and asked specifically whether all U.S. attorneys would be fired at once,” Feinstein added. “McGahn told me that the transition would be done in an orderly fashion to preserve continuity. Clearly this is not the case. I’m very concerned about the effect of this sudden and unexpected decision on federal law enforcement.”

Senator Elizabeth Warren (D-Mass.), one of President Trump’s staunchest critics, took to Twitter with a stern warning: “You’re not replacing real prosecutors with cronies without a massive fight.”