Donald Trump has hit out at reports that considerably fewer people turned out to watch him take the oath of office than at Barack Obama's first inauguration and warned a "big price" will be paid by reporters who allegedly lied about the size of the crowds at his inauguration ceremony.
Pictures shared on social media appeared to show acres of empty space on Washington DC's National Mall where an estimated 1.8 million people stood to see his predecessor in 2009.
However, the new president insisted that his was "the largest audience to ever witness an inauguration - period" and slammed the reports as "shameful".
Speaking at the CIA headquarters in Virginia on his first full day in office, Mr Trump said the reports did not reflect the scene from his vantage point on Capitol Hill.
He also attacked reporters as being among the "the most dishonest human beings on Earth."
"We had a massive field of people, you saw them - packed. I get up this morning, I turn on one of the networks and they show an empty field," Mr Trump said.
"I said 'wait a minute, I made a speech', I looked out the field was, it looked like a million, a million and a half people, they showed a field where there were practically nobody standing.
"Honestly it looked like a million and a half people, whatever it was, it was. But it went all the way back to the Washington monument."
The new White House press secretary Sean Spicer also chided the news media for what he called "deliberate false reporting" regarding the attendance at figures at the inauguration.
Talking at his first press briefing, Mr Spicer spoke for about 10 minutes, before walking out without taking any questions.
"Yesterday, at a time when our nation and the world was watching the peaceful transition of power ... some members of the media were engaged in deliberate and false reporting," he said.
Launching into a lengthy explanation over photos on which appeared to show swathes of empty space at the ceremony on social media, he insisted: "This was the largest audience to ever witness an inauguration - period. Both in person and around the globe."
He said: "Photographs of the inauguration process were intentionally framed in a way ... to minimise the enormous support that had gathered on the National Mall," he said.
The area between the Capitol building and the Washington Monument, just over halfway down the National Mall, held approximately 720,000 people, he added.
"All of this space was full when the president took the oath of office," he said.
"He added:"This was the first time in our nation's history that floor coverings had been used to protect the grass on the Mall that had the effect highlighting any areas where people were not standing, while in years past, the grass eliminated this visual. This was the largest audience to ever witness an inauguration, period – both in person and remote."
However, similar coverings were used on the Mall during Mr Obama's inauguration in 2013.
Estimates place attendance of Mr Trump's inauguration at around 250,000, although there are no official figures.
“No one had numbers because the National Park Service, which controls the National Mall, does not put those out,"Mr Spicer said.
He added that 420,000 people used the DC Metro Transit on Friday, compared to 317,000 who used it for President Obama's last inauguration in 2013. He did not say how many used the system in 2009.
Nielsen estimates that 31 million viewers watched TV coverage of President Trump's inauguration.
That is better than Mr Obama's second inauguration but well short of his first.
The most-watched inauguration since 1969 was President Ronald Reagan's first oath-taking in 1981, which was seen by 41.8 million people. The audience total measures continuous coverage by 12 broadcast and cable networks.
In 2013, 20.6 million viewed Mr Obama's second inauguration. His first inauguration, in 2009, was seen by 37.8 million people.
Around 1.8 million people also attended the live event in Washington DC.
Mr Spicer also said that the Trump administration were “going to hold the press accountable,” partly by reaching the public through social networking sites.
Meanwhile, more than 500,000 demonstrators marched on the nation's capital the day after the presidential inauguration – and hundreds of thousands and possibly millions more took to the streets in all 50 states and around the globe.