Washington (CNN) President Donald Trump moved fast to mend his relationship with the CIA on just his second day in office, then ignited a feud with the media over the size of his inauguration crowd after mass nationwide protests erupted against his administration.

A day after he set the tone for his term by delivering a searing inaugural address laced with the populist themes that helped him win the election, Trump offered new evidence that he will be as disdainful of convention and protocol as President as he was in the campaign trail.

His broadside against the media, which he believes is unfairly representing the size of the crowd on Friday, and the sight of huge anti-Trump crowds in US cities and around the world also made another thing clear: the political acrimony that rattled the nation for the past 18 months is not going away.

Trump traveled to the CIA headquarters in Langley, Virginia, for a briefing from senior agency leaders and spoke to several hundred people in the spy agency's foyer, in front of a hallowed spot: the wall of honor where fallen operatives are remembered with stars.

"This is my first stop officially, there is nobody that feels stronger about the intelligence community and the CIA than Donald Trump, there is nobody," Trump said. "I am so behind you and I know that maybe sometimes you haven't got the backing that you wanted."

The gesture of the visit was an important moment for Trump, who raised doubts about his relationship with US intelligence agencies by initially casting doubt on their assessment that Russia intervened in the election by hacking Democratic email accounts. He had also spurred anxiety about his willingness to accept traditional presidential daily briefings on the gravest security threats facing the United States.

His comments were warmly received by CIA employees who came in on a Saturday to see their new president.

But Trump also departed from his topic, turning the event into a campaign-like appearance.

He complained about the media's treatment of him and accused television stations of not being truthful about the size of the crowd on Friday.

"I have a running war with the media, they are among the most dishonest human beings on Earth -- they sort of made it sound like I had a feud with the intelligence community. The reason you are the number one stop is exactly the opposite," he said.

Later, White House press secretary Sean Spicer appeared in the White House briefing room to warn the administration was going to hold the press "accountable" and argued that the Trump crowd was the largest inaugural crowd ever. He said any suggestion otherwise was "shameful and wrong."

Spicer then left the room after the statement without taking questions.

The White House appeared irked by cameras that showed large gaps in Trump's still large crowd on Friday compared to the one that showed historic numbers of spectators to see former President Barack Obama sworn in for his first term in 2009.

The chairman of Trump's inaugural committee, Tom Barrack, told CNN's Michael Smerconish that Trump was disappointed at what he saw as deceptive photos of the crowd that appeared on Twitter.

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"I think it's appropriate because this president is just putting his fingerprint on what it's going to be like for him to be president. It's the same consistency of straight talk," Barrack said.

The spat was another reminder of Trump's deep sensitivity to criticism and to any suggestion that his popularity or election victory are not entirely legitimate.

Protests around the country

As Trump adjusted to the reality of power, those opposed to his presidency sent their own message, as a huge crowd gathered in Washington for a women's march and demonstrators also thronged cities including Chicago, Boston and Seattle. Protests also took place across the world, including in Sydney, Australia, London, Paris and Berlin.

The President's motorcade passed some of the protesters as he left the White House for the CIA. The protests were part of a grassroots organizing effort meant to demonstrate a show of force to the new administration that women's rights are human rights and to stress respect for racial, gender and political diversity that organizers say were threatened by Trump's campaign.

The plan had been to march on the White House but the larger-than-expected crowd in Washington clogged the planned route.

At another big rally in Boston, Massachusetts Sen. Elizabeth Warren said Trump's presidency should serve as a rallying point for progressives.

"Yesterday, Donald Trump was sworn in as President. That sight is now burned into my eyes forever and I hope the same is true for you," Warren told the crowd.

"We will not forget, we don't want to forget. We will use that vision to make sure we fight harder, we fight tougher and we fight more passionately than ever."

Clergy calls for unity at National Cathedral

Earlier, at Washington's National Cathedral, Trump took part in the traditional inauguration prayer service, as clergy from various faiths including Christianity, Judaism, Hinduism and Islam offer prayers for his administration and the nation.

In his opening prayer, the Very Reverend Randolph Marshall Hollerith, the dean of Washington National Cathedral, appeared to be making a point about the need for unity after the bitter, divisive election campaign that made Trump president.

"Look with compassion on the whole human family; take away the arrogance and hatred which infect our hearts; break down the walls that separate us; unite us in bonds of love; and work through our struggle and confusion to accomplish your purposes on earth; that, in your good time, all nations and races may serve you in harmony around your heavenly throne through Jesus Christ our Lord," Hollerith said, reciting an excerpt from the Book of Common Prayer.

Trump, who was accused of discrimination against followers of Islam throughout the campaign, also sat quietly as a Muslim prayer echoed through the nave.

Imam Mohamed Magid, executive director of the All Dulles Area Muslim Society, had been expected to deliver the Islamic call to prayer, but instead recited two verses from the Quran that contained clear political messages for the new president and his administration.

The President did not speak at the service.

World worries about speech

Trump was still buzzing on Saturday morning after the day of ceremony the day before.

"A fantastic day and evening in Washington D.C.Thank you to @FoxNews and so many other news outlets for the GREAT reviews of the speech!" Trump said in the first tweet from his personal Twitter account of his presidency.

A fantastic day and evening in Washington D.C.Thank you to @FoxNews and so many other news outlets for the GREAT reviews of the speech! — Donald J. Trump (@realDonaldTrump) January 21, 2017

Hours earlier, he swept into several inaugural balls with First Lady Melania Trump, and the couple danced to Frank Sinatra's "My Way." The President told the crowd at one event that even people who had not been nice to him said "we did a really good job today. They hated to it but they did it. And I respect that. I respect that."

The impact of Trump's inaugural address was reverberating around the world on Saturday. Foreign newspapers narrowed in on the nationalistic turn in US foreign policy.

"Trump offers fearful vision as he promises 'America First,'" the Irish Times said in a front page splash. The Dawn newspaper in Pakistan highlighted Trump's inaugural vow to unite the world against "radical Islamic terrorism."

One of the world's most important leaders, German Chancellor Angela Merkel, pledged to work with Trump to find "compromises and solutions" on the basis of mutual respect. Asked at a news conference about Trump's address and its America-first tone, she said: "I believe firmly that it is best for all of us if we work together based on rules, common values and joint action in the international economic system, in the international trade system, and make our contributions to the military alliances."

"And second, the trans-Atlantic relationship will not be less important in the coming years than it was in past years."

Trump raised eyebrows in an interview while he was still President-elect in which he said he had similar levels of respect for Merkel and Russian President Vladimir Putin, who is widely regarded as a US enemy in Washington.

First orders signed by Trump

Before spending his first night in the White House, Trump moved quickly to consolidate his power and to make an immediate break with the Obama administration. He signed an executive order that will begin the process of chipping away at the Affordable Care Act, the centerpiece of former President Barack Obama's domestic legacy.

The 45th President also signed documents validating the appointments of his newly confirmed cabinet members Defense Secretary James Mattis and Homeland Security Secretary John Kelly. Other cabinet picks, including the incoming CIA director Mike Pompeo, are expected to receive votes from Monday, though partisan wrangling is still delaying many cabinet appointments.

White House Chief of Staff Reince Priebus sent out a memo to all government agencies and departments calling for a freeze on new regulations.

Some changes were already evident in the Oval Office Friday night. Red drapes had been replaced with yellow drapes. A bust of Winston Churchill had been returned after an eight-year absence during the Obama administration. And the carpet was a new sunburst pattern.