The acting attorney general informed the Trump White House late last month that she believed Michael Flynn had misled senior administration officials about the nature of his communications with the Russian ambassador to the United States, and warned that the national security adviser was potentially vulnerable to Russian blackmail, current and former U.S. officials said.

The message, delivered by Sally Q. Yates and a senior career national security official to the White House counsel, was prompted by concerns that ­Flynn, when asked about his calls and texts with the Russian diplomat, had told Vice ­President-elect Mike Pence and others that he had not discussed the Obama administration sanctions on Russia for its interference in the 2016 election, the officials said. It is unclear what the White House counsel, Donald McGahn, did with the information…

In the waning days of the Obama administration, James R. Clapper Jr., who was the director of national intelligence, and John Brennan, the CIA director at the time, shared Yates’s concerns and concurred with her recommendation to inform the Trump White House. They feared that “Flynn had put himself in a compromising position” and thought that Pence had a right to know that he had been misled, according to one of the officials, who, like others, spoke on the condition of anonymity to discuss intelligence matters.

A senior Trump administration official said before Flynn’s resignation that the White House was aware of the matter, adding that “we’ve been working on this for weeks.”