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The Trump administration’s sudden request on Friday that all 46 U.S. attorneys resign was met with surprise by multiple federal prosecutors, with at least one first finding out about the demand on social media, a source close to the U.S. attorney told NBC News.

"We saw it on Twitter," said the source, who is not the prosecutor and who requested anonymity because he was not authorized to speak publicly about the matter.

At that point the source says the press office in that district notified the U.S. attorney about the press release from the Department of Justice and tweets from reporters.

The U.S. attorney was wholly unaware that he was expected to resign Friday and had not been notified about the public announcement prior to the press release being received.

The source says the U.S. attorney and other U.S. attorneys were surprised because on a Thursday conference call with Attorney General Jeff Sessions he concluded the call by telling them "happy hunting!" Sessions, the source says, had given no indication about Friday’s announcement.

All 93 U.S. attorneys — the top federal prosecutors in the states — are political appointees. A total of 47 had already stepped down. Some states, divided into separate districts, have more than one.

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It has been done before. In 1993, Attorney General Janet Reno demanded the resignations of all 93 U.S. attorneys in the early days of the Clinton administration.

A Justice Department statement said the action was taken "as was the case in prior transitions."

Related: Trump Administration Tells Remaining U.S.Attorneys to Resign

The source said that he was aware that some U.S. attorneys had been told in recent weeks that they would be replaced. However, they were told by Justice Department headquarters that they would have a month or even longer (in some cases until May) to resign.

Later, after the press release was sent out, the source said the U.S. attorney and some of his colleagues heard directly from Washington that they were to resign.

When the U.S. attorney got the call he was told to clear out and submit his resignation by midnight, according to the source.

The source says the U.S. attorney and his colleagues were caught by surprise.

In addition, two sources say that the presumed acting U.S. attorneys who would replace the Obama appointees ‎had not been called by Justice Department as of late Friday evening in multiple districts.

The source says it was not lost on the resigning U.S. attorney and colleagues he says he talked to that there was no customary "thank you" for their service in the Justice Department’s press release announcing the move.

The source noted that being asked to resign was not surprising in the least. But the source says the manner in which it happened was both angering and deeply disappointing, according to conversations the source was privy to among several U.S. attorneys.

U.S. Attorney General Preet Bharara of New York announced that he had been fired Saturday after refusing to submit his resignation as requested by the administration on Friday. Bharara said he'd been asked by President Donald Trump to stay on as attorney general after meeting with him in late November.

Bharara was appointed by Obama in 2009 and has a reputation of being tough on corruption and crime involving Wall Street executives.

Senate Minority Leader Chuck Schumer, a Democrat who represents New York, took exception on Friday to Bharara being asked to resign.

"By asking for the immediate resignation of every remaining U.S. Attorney before their replacements have been confirmed or even nominated, the President is interrupting ongoing cases and investigations and hindering the administration of justice,” Schumer said in a statement.