Fox News anchor Chris Wallace confronted White House chief of staff Reince Priebus on Sunday over the White House's dubious claims about the size of the crowd at Trump's inauguration.
"What it's about is on Day One after winning this election and President Trump talking about bringing America together ... however, the media from Day One has been talking about delegitimizing the election, talking about the Russians, talking about everything you can imagine except for the fact that we need to move this country forward". And we're not going to sit around and let it happen.
But photos appear to show more people attended the inauguration of Mr Trump's predecessor Barack Obama in 2009.
White House Chief of Staff Reince Priebus said there was "an obsession.to de-legitimise this president".
Top White House aide Kellyanne Conway told NBC's "Meet the Press " Sunday that Spicer provided "alternative facts" to reporters during his press briefing on Saturday afternoon". "How does arguing about crowd size do that?" "We're gonna fight back tooth and nail every day, and twice on Sunday".
He repeated White House press secretary Sean Spicer's charges on Saturday that the media had manipulated photographs of the National Mall to show smaller crowds on Friday.
Host Chuck Todd though fire back, saying alternative facts "are not facts".
He also referred to Saturday's day of protests that saw millions in the U.S. and hundreds of thousands around the globe take to the streets in some 600 demonstrations against his presidency.
Mr Trump said during a visit to the Central Intelligence Agency on Saturday that it "looked like a million and a half people", but provided no evidence.
"This was the largest audience to ever witness an inauguration, period - both in person and around the globe", he said.
He said the media's estimation that 250,000 people had attended his ceremony was "not bad", but it was a "lie".
Spicer blamed the poor visuals of the inauguration on floor coverings protecting the grass, saying they highlighted empty spaces.
Mr Trump toyed with the media again on Sunday when at an event in the White House he showed an envelope that he said he found in the Oval Office that contained "a handsome letter" from Mr Obama.
Spicer did not take questions from the media.