Principal deputy press secretary Raj Shah says: "We frequently face rumour and innuendo about senior administration officials".
Secretary of Defense James Mattis' office referred all questions regarding personnel matters to the White House.
The three-star general's appointment followed the resignation of Trump's first national security adviser, Gen. Michael Flynn, over secret talks with the Russians.
Since then, McMaster's relationship with Trump has stabilized, even as rumors of his imminent departure have swirled.
Mummies with the oldest tattoos
The practice of tattooing appears to be 1,000 years older than anyone knew. Mr Antoine told The Times: "It is the earliest use of figurative tattoos".
On Wednesday, the White House confirmed that communications director Hope Hicks planned to leave in the coming weeks.
McMaster's statements and views have found himself often at odds with President Donald Trump.
"He still has confidence in General McMaster", Sanders said during a briefing. "I was just with President Trump and H.R. McMaster in the Oval Office".
At today's White House press briefing, White House Press Secretary Sarah Huckabee Sanders was grilled briefly on the recent controversies surrounding senior advisor (and President Donald Trump's son-in-law) Jared Kushner that have popped up in recent days. The president, she said Friday, thinks McMaster is doing a "great job". McMaster is now overseeing some of the most sensitive issues facing the White House, such as efforts to counter Iran's expanding role in the Middle East and the administration's strategy to roll back North Korea's nuclear weapons program.
McMaster joined the administration in February previous year, replacing Michael Flynn, who has since been indicted by Robert Mueller, who is investigating Russia's role in Trump's election - and possible collusion between Team Trump and Moscow.
However, sources tell Garrett that the tension regarding McMaster is real, and that an exit strategy may now be in the works.