Law enforcement is investigating the death of H.R. McMaster Sr., the father of President Donald Trump's former national security adviser.
The shakeup plays out while Trump's new pick for secretary of state, Mike Pompeo, awaits confirmation by Congress.
Since Bolton accepted the job two weeks ago to replace H.R. McMaster, the Trump administration has ratcheted up its already extensive array of national security challenges.
White House lawyers and Bolton continue to discuss and review any potential conflicts of interests for the former U.N. ambassador, sources with direct knowledge of the matter told CNBC on the condition of anonymity.
Shulkin has been under fire for two critical internal watchdog reports, including one that found his wife's travel to Europe with him last year had been improperly paid for by taxpayers.
The briefing also follows the appointment of John Bolton to replace H.R. McMaster as the president's national security advisor.
Former U.S. Secretary of Defense William Cohen said he had reservations about whether North Korea would actually get rid of all its nuclear weapons.
The new recruits — Bolton, Kudlow and Pompeo — diverge from their predecessors on ideology, experience and style.
If the omnibus spending bill doesn't pass by 12:01 a.m. Saturday, the government will shut down.
"My greatest concern is that the president is dealing with each of these pieces in silos, without understanding how they all interconnect," she told CNBC.
U.S. President Donald Trump's choice of John Bolton to replace H.R. McMaster as national security advisor replaces a restraining influence in the president's inner circle with a dedicated hawk.
McMaster is the second national security advisor to leave the Trump administration in just over one year.
The Saudi delegation is slated to meet with defense industry giants Lockheed Martin and Boeing.
After a tumultuous week in the West Wing, chief of staff John Kelly reassured staff Friday that there would be no resignations in the immediate future.
Press secretary Sarah Huckabee Sanders denied reports that national security advisor H.R. McMaster would be replaced.
U.S. crude oil futures suddenly spiked more than 1 percent late Friday morning, erasing losses for the week.
European stocks finished Friday's session in the black, as investors tried to shake off concerns surrounding trade and political disruption in the White House.
The dollar rose against most currencies on Friday, bolstered by solid U.S. economic data.
Gold prices were set for their biggest weekly fall in three weeks.
Trump has parted with more top-level staff in his first year than any of his five most recent predecessors did in their respective first years.