Michael Flynn’s overnight resignation as national security adviser was driven in part by intervention from Vice President Mike Pence and White House Chief of Staff Reince Priebus, well-placed sources tell Fox News.

The retired general’s resignation followed mounting controversy over reports he spoke with the Russian ambassador about sanctions, despite apparently having told Pence otherwise. While the White House for days had given mixed signals about Flynn’s fate, sources told Fox News that Priebus personally told President Trump that Flynn had to go.

Hours earlier, in Flynn's morning meeting with Trump, sources said, Flynn had made the case that the inaccuracies in his communications with the vice president were truly inadvertent, and that he had never sought to hide his discussions with Ambassador Sergey Kislyak -- at which point the president told Flynn to go out and defend himself.

Flynn then chose -- reportedly without informing senior staff -- to conduct an interview with Eli Lake of Bloomberg View, who is seen by Flynn as a fair journalist.

At the same time, the White House senior staff was riven with dissension over Flynn's fate.

Sources said advisers Steve Bannon and Kellyanne Conway were arguing that the national security adviser should be allowed to stay on, at least for now. The sources said that once senior staff learned about the pending interview with Lake, however, Priebus went to the president to get it shut down.

As late as 9:30 p.m. ET, some Republicans on Capitol Hill were urging the administration to allow Flynn to stay another six-to-nine months, so that he could build out the NSC staff and the administration could avoid serving up to Democrats a high-profile political scalp so early.

"Now there's blood in the water," one source said.

Other sources, from within the camp that favored Flynn’s departure, told Fox News that the president’s displeasure with Flynn had been building for some time, starting with the flap over his son’s dismissal from the transition team, and that even some top intelligence officials considered Flynn “nutty.”

“God help us,” one spymaster confided to a colleague, “if Flynn’s the last one in there with [the president].”

One source, who agreed with the decision that Flynn had to go, told Fox News: “You can’t lie to the vice president when you’re on tape.”

The arguments advanced by Priebus and others for not allowing Flynn a face-saving six-to-nine more months on the job were that this story was going to stay in the headlines and become a worsening liability for the administration; and that Flynn should not build out an NSC staff he would not be around to manage.

Flynn, in his resignation letter, again insisted he had “inadvertently” briefed Pence and others with “incomplete information” on his calls with the Russian ambassador.

“I have sincerely apologized to the President and the Vice President, and they have accepted my apology,” he wrote.

After his resignation was accepted, Flynn told Fox News, "I have nothing to be ashamed for and everything to be proud of."

While the departure of Flynn contributes to the appearance of a White House in turmoil, officials believe the story will soon be forgotten amid bigger, more defining events – most immediately, the president’s meeting with Israeli Prime Minister Benjamin Netanyahu and the forthcoming address to a joint session of Congress.

Fox News’ James Rosen contributed to this report.