The country's No. 2 intelligence official, Sue Gordon, knew it was likely she would have to eventually step down from her post, but the timing of that decision became more urgent on Thursday after her boss -- outgoing spy chief Dan Coats -- interrupted a meeting she was holding on election security and asked his deputy to submit her letter of resignation, sources familiar with the events told CNN.

President Donald Trump abruptly announced in a tweet Tuesday that he has asked national security adviser John Bolton to resign, noting that he "strongly disagreed with many" of Bolton's suggestions "as did others in the administration."

Long-simmering tensions between top figures on President Donald Trump's national security team have devolved into all-out hostility, creating a deep disconnect between staffers on the National Security Council, led by John Bolton, and the rest of the administration, six people familiar with the matter said.

President Donald Trump is seriously considering a plan to block $250 million in military assistance to Ukraine, a move that would further ingratiate him with Russian President Vladimir Putin, and has directed senior officials to review the aid package.

President Donald Trump praised his pick for acting director of national intelligence, Joseph Maguire, as an "excellent" choice and a "very talented man" Friday, but it remains unclear where the new acting spy chief stands on some of the most pressing national security issues facing the country today.

The White House has gone back to the drawing board in its search for a new nominee to be the nation's top intelligence official after President Donald Trump's first choice, Rep. John Ratcliffe, abruptly withdrew from consideration last week.