Key figures in Donald Trump's administration have become embroiled in a fresh war of words with the media.
On Saturday the president had condemned media reporting of the number of people attending his inauguration.
White House Chief of Staff Reince Priebus said there was "an obsession... to de-legitimise this president. We're not going to sit around and take it."
But photos show more people attended the inauguration of Mr Trump's predecessor Barack Obama in 2009.
Mr Priebus said on Fox News Sunday that the "media from day one has been talking about de-legitimising the election". He said Mr Trump's presidency would fight such coverage "tooth and nail every day".
The latest row was mainly sparked by the inauguration figures.
There were no official estimates. Mr Trump said during a visit to the CIA on Saturday that it "looked like a million and a half people", but provided no evidence. He called reporters "among the most dishonest human beings on Earth" for saying it was far lower.
His press secretary Sean Spicer outlined figures amounting to 720,000 people in Washington's National Mall, despite also saying that "no-one had numbers" for the inauguration.
Many US outlets, using photos of the National Mall showing the difference in numbers attending the 2009 inauguration and Mr Trump's, hit out at Mr Spicer's statements.
The New York Times denounced "false claims" and described the statements as a "striking display of invective and grievance at the dawn of a presidency".
Both CNN and ABC News went into detail to refute Mr Spicer's claims.
Top Trump aide Kellyanne Conway also criticised the media during a heated exchange on NBC.
She was challenged by presenter Chuck Todd who asked her why Mr Spicer's first appearance had been to "utter a provable falsehood".
"If we are going to keep referring to our press secretary in those type of terms, I think we are going to have to rethink our relationship here," she said.
Pressed on Mr Spicer's claims, she said he had been presenting "alternative facts".
"Alternative facts are not facts. They are falsehoods," Todd replied.
Ms Conway insisted there was "no way to really quantify crowds" and, taking offence at a laugh from the reporter, said: "You can laugh at me all you want. It's symbolic of the way we are treated by the press the way you just laughed at me."
She also highlighted another issue that caused friction with the media - the Time Magazine reporter who incorrectly reported that a bust of civil rights hero Martin Luther King Jr had been removed from the Oval Office. The reporter later apologised for the error.
"It puts lives at risk" - US media denounce "false claims"
- The Washington Post said the falsehoods from the White House showed that "the traditional way of reporting on a president is dead". In future, news organisations should pay less attention to official statements, and instead focus on investigations into Mr Trump's administration, it said
- Politico warned of "grave consequences" of the Trump team's "rocky relationship with the truth", quoting Democrat congressman Adam Schiff saying that "it absolutely puts lives at risk". The idea that the White House's "combative approach" could also apply to "substantive matters of government and national security... has many really worried", the website said
- The Atlantic magazine also worried where the administration's approach could take the country, saying: "If you're willing to lie about stuff this minuscule, why should anyone believe what you say about the really big things that matter?"
- The Huffington Post was among those that called for a change in the way news organisations cover statements from the White House. "They should focus attention on the fact that the administration lied, not the content of the lie itself," it said
Mr Trump on Sunday tweeted about television ratings of the inauguration, saying that 31 million people had watched, 11 million more than four years ago.
On Saturday, US ratings firm Nielsen said nearly 31 million had watched the inauguration on television - higher than the 20.5 million that watched Mr Obama's second inauguration in 2013. However, that was far fewer than the 38 million that watched Mr Obama's first inauguration in 2009 and the 42 million that watched Ronald Reagan's first swearing-in in 1981, casting further doubts about Mr Spicer's claims of the "largest audience ever".
In his tweets, Mr Trump also referred to Saturday's day of protests, when millions in the US and hundreds of thousands around the globe took to the streets in some 600 demonstrations against his presidency.
His initial tweet said he was "under the impression that we just had an election", asking: "Why didn't these people vote?"
A later tweet said that "peaceful protests are a hallmark of our democracy".
In other Sunday morning media exchanges:
- Kellyanne Conway told CBS programme Face the Nation that 20 million people relying on the soon-to-be-repealed Affordable Care Act, known as Obamacare, would not go without health care coverage during the transition to a new plan
- Ms Conway repeated that Mr Trump was not going to release his tax returns
- Reince Priebus said Mr Trump's first full week in office would focus on trade, immigration and national security
- Senior Trump ally Ted Malloch told the BBC that Nato would be reformed, with the possibility of "new institutions" and a definite focus on ensuring European members paid more towards the alliance