By Abby Phillip – The Boston Globe.

WASHINGTON — President Donald Trump was aware that his national security adviser Michael Flynn had misled White House officials and Vice President Mike Pence for ‘‘weeks’’ before he was forced to resign on Monday night.

Trump was briefed by White House Counsel Don McGahn that Flynn had discussed U.S. sanctions with the Russian ambassador Sergey Kislyak, despite his claims to the contrary ‘‘immediately’’ after McGahn was informed about the discrepancy by the Department of Justice, White House press secretary Sean Spicer said Tuesday.

Sally Yates, the acting Attorney General at the time, and a senior career national security official at the Justice Department had informed McGahn at his office about their concerns on Jan. 26, according to a person familiar with the briefing. Spicer said that the president and a small group of senior aides were briefed by McGahn about Flynn that same day.

‘‘We’ve been reviewing and evaluating this issue with respect to General Flynn on a daily basis for a few weeks, trying to ascertain the truth,’’ Spicer said.

The comments appear contradict the impression given by Trump on Friday aboard Air Force One that he was not familiar with a Washington Post report that revealed that Flynn had not told the truth about the calls.

‘‘I don’t know about that. I haven’t seen it. What report is that? I haven’t seen that. I’ll look into that,’’ Trump told reporters on the plane.

The White House Counsel’s office conducted a ‘‘review’’ of the legal issues and determined that ‘‘there was not a legal issue but rather a trust issue,’’ Spicer said. ‘‘The president was very concerned that General Flynn had misled the vice president and others. The president must have complete and unwavering trust of the person in that position.’’

Spicer said that ‘‘the evolving and eroding level of trust as a result of a series of other issues is what led the president to ask for General Flynn’s resignation.’’ He added that the president had an ‘‘instinctive’’ belief that Flynn had not broken any laws, which was later ‘‘confirmed’’ by an inquiry led by the White House counsel’s office.

Spicer’s account of the event that led to Flynn’s resignation adds to the confusion among White House officials on that issue. Senior officials told reporters on Monday night that Flynn offered his resignation voluntarily. And White House counselor Kellyanne Conway said on the ‘‘Today’’ show Tuesday morning that Flynn ‘‘had resigned’’ and was not forced to quit.

‘‘The president is very loyal. He’s a very loyal person,’’ Conway said. ‘‘And by nighttime, Mike Flynn had decided it was best to resign. He knew he became a lightning rod, and he made that decision.’’

The press secretary repeatedly said that Trump was not concerned with the nature of the conversations that Flynn had with the Russian ambassador but that the lack of trust created an ‘‘unsustainable’’ situation.

‘‘The president has no problem with the fact that he acted in accord with what his job was supposed to be,’’ Spicer said.

National security officials monitored the calls of the Russian ambassador as a part of routine surveillance of foreign officials in the U.S. Spicer declined to say if the president would declassify and release transcripts of Flynn’s call with Kislyak.

‘‘It is inappropriate for me to comment on those a this time,’’ Spicer said. ‘‘It is not an issue that has come up.’’