Mira Ricardel, the deputy national security adviser and top aide to national security adviser John Bolton, reportedly had spats with the first lady over her trip to Africa last month, with the first lady calling for her ouster. Nielsen worked on disaster-management response in the Bush White House, then in the private sector and academia as a cyber security expert before returning to DHS to work as chief of staff under Kelly when he was Homeland Security secretary during Trump's first six months in office.
He reportedly told Kelly to give the first lady whatever she wanted, adding: 'I don't need this shit'.
Mira Ricardel is the current deputy national security advisor for the White House.
"It's been frayed for a long time", the source said, cautioning Trump could again change his mind on the matter.
Mr Trump cancelled a planned trip with Ms Nielsen this week to visit United States troops at the border in south Texas and told aides over the weekend he wants her out as soon as possible, these officials said.
Hamas threatens to step-up rocket fire at Israel
A Hamas commander, six other Palestinian terrorists and an IDF officer were killed in Sunday's exchanges of fire. Earlier Monday, thousands of Palestinian mourners buried the seven militants killed in Sunday's incursion.
Khashoggi audio makes apparent reference to Saudi Crown Prince, NYT reports
Bolton said he did not think that people who heard the recordings concluded that the crown prince was linked to the killing. Ankara insists the orders for the killing came from the highest levels of the Saudi government , but not King Salman .
Heavy rain Tuesday, more rain Thursday and Friday with some snow possible
We'll keep an eye on this event, as this particular model may be going a little on the low side with forecast amounts. Tuesday will be a cloudy, brisk and cold day overall with spotty flurries and slowly falling afternoon temperatures.
Senior White House adviser Kellyanne Conway attempted to cast doubt Tuesday on the anonymously sourced reports about a staff shake-up.
Trump is also considering replacing Kelly, an ardent defender of Nielsen, with Vice President Mike Pence's chief of staff, Nick Ayers, the Reuters source said.
Nielsen had hoped to complete one year in the job and leave in December, but it appeared unlikely she would last that long, said two sources.
Trump is said to have this weekend told advisers of his plan to get rid of her as Nielsen's one-year job anniversary of December 6 approaches.
The National Security Council (NSC) had no immediate comment.
Now it's alleged the American leader wants someone with a more aggressive attitude to curtailing immigration but with no deputy secretary since April, Nielsen's responsibilities could land in Claire M. Grady's lap.
Mr. Trump forced out Jeff Sessions as attorney general the day after the midterm elections.
It's not clear who would succeed her, or whether the White House has potential replacements lined up.