President Trump delivered on more campaign promises Monday by implementing a hiring freeze for most federal agencies, withdrawing from a major trade agreement and urging corporate executives to keep jobs in the country.

But his aides also signaled that the new administration will not move as quickly as Trump had promised earlier on other top priorities, including renegotiating the long-standing North American Free Trade Agreement ­(NAFTA) and undoing President Barack Obama’s executive orders on immigration, including a policy that allows some undocumented immigrants who came here as children to stay lawfully.

Trump’s clearest shot at what he has derided as Washington’s broken system of governing came in the form of the hiring freeze. The president and his aides have portrayed federal agencies as bloated and wasting money.

But even the hiring freeze may promise more than it can deliver. It provided exemptions for those working in the military, which could include civilian employees, potentially leaving a large part of the federal workforce untouched by the order.

Trump kicked off his first full workweek with a whirlwind of activity — a breakfast with corporate leaders followed by a call with Egyptian President Abdel Fatah al-Sissi and meetings with union workers and congressional leaders.

(Bastien Inzaurralde/The Washington Post)

Throughout the day, Trump maintained a heavy focus on trade, which was at the heart of his presidential campaign and one of the few areas in which he did not shift among positions. And he often seemed comfortably at home in the White House as he entertained, signed orders, posed for photos and promised to disrupt Washington, just as he had electoral politics.

Monday opened with a “listening session” with leaders of some of the country’s largest corporations — who stayed longer than planned to continue talking with Trump in the Oval Office. The president promised the group that he would cut taxes, fast-track their plans to open factories and wipe out at least 75 percent of government regulations.

“We’re going to be cutting regulation massively,” Trump said during a brief portion of the meeting that was open to the news media. “Now, we’re going to have regulation, and it’ll be just as strong and just as good and just as protective of the people as the regulation we have right now.”

In exchange, Trump said companies must stay in the country and continue employing Americans. He again threatened to impose a “substantial border tax” on companies that move production out of the country. International-trade analysts said Trump may not have the authority to punish individual companies, while broad-based tariffs would violate existing treaties. Trump defended his idea as “fair.”

“Don’t leave,” Trump said. “Don’t fire your people in the United States. We have the greatest people.”

After the meeting, Andrew Liveris of Dow Chemical told reporters that Trump and the chief executives discussed the border-tax proposal and the industries it would help or hurt. But Liveris added that Trump “is not going to do anything to harm competitiveness. He’s going to actually make us all more competitive, recognizing there’s a transition here. You can’t get things done overnight.”

Later in the morning, reporters witnessed Trump signing three pieces of paper that were briefly described aloud by White House Chief of Staff Reince Priebus as he handed them to the president. These documents, labeled executive orders by aides, were not released to the media or the public until late in the day, leaving many to wonder for hours what exactly the president was implementing.

First Trump signed a memorandum ordering the formal end of the United States’ participation in the Trans-Pacific Partnership (TPP), a long-standing campaign promise, although the move at this point is considered largely symbolic because the trade deal had little chance of being approved by Congress.

“We’ve been talking about it for a long time,” Trump said as he held up the order. “Great thing for the American worker.”

Trump had also promised to take steps on his first formal day in office to begin renegotiating NAFTA, but that deal went unmentioned Monday. Trump earlier said he will meet soon with the Canadian prime minister and the Mexican president to discuss renegotiating the agreement.

Then came an executive order that would implement a hiring freeze for many jobs in the federal government, another promise Trump made on the campaign trail.

“Except for the military,” the president said as he signed the order. “Except for the military.”

Finally, Trump signed an order resurrecting an abortion-related rule known as the Mexico City policy. The policy prohibits foreign nongovernmental organizations that receive federal funding from performing or promoting abortion services through their work in other countries. The policy takes its name from the location of a conference at which President Ronald Reagan instituted the restriction in 1984.

Since that time, the rule has been in place under Republican presidents while being lifted by Democratic residents of the Oval Office.

This signing seemed more like a party tradition than a new push by Trump, who had never mentioned the rule on the campaign trail. But he promised evangelical voters that he would remain opposed to abortion.

As reporters left the Oval Office, one asked the president about the lawsuit filed by a liberal watchdog group that alleges that Trump is in violation of a little-known constitutional provision that bars him from taking gifts or payments from foreign governments.

“Without merit,” Trump said. “Totally without merit.”

Soon attention shifted to Trump’s press secretary, Sean Spicer, who endured rounds of criticism and mockery for delivering a blistering statement Saturday in the White House briefing room that accused the media of underestimating Trump’s inauguration crowd size and relied on a number of statistics that quickly proved to be inaccurate.

Spicer held his first formal briefing Monday afternoon to a standing-room-only crowd, opening with a joke about being less popular than his predecessor, Obama press secretary Josh Earnest.

The joke fell flat.

Spicer proceeded to answer questions for nearly 80 minutes, calling on more than three dozen reporters from a wide range of news outlets.

Even as he patiently worked the room, Spicer did not back down from his contention that the press was out to “undermine” the president, and he continued to insist that Trump’s inauguration was the most watched in history, after television and Internet viewers were accounted for, without offering full evidence to back his claim.

“There’s this constant attempt to undermine his credibility and the movement that he represents,” Spicer said. “And it’s frustrating for not just him, but I think so many of us that are trying to work to get this message out.”

Spicer was asked why Trump was not following through on more of the campaign promises he pledged to fulfill on his first day in office.

“Part of it is to make sure that we don’t spend our entire day signing executive orders,” he said. “There’s a way that we can do this to make sure that we’re getting all of those things that he promised the American people done in short haste and doing it in a way that doesn’t just jam them out in a fire hose.”

Spicer also said that there had been “no decision” on moving the U.S. Embassy in Israel from Tel Aviv to Jerusalem, a Trump campaign promise that the president’s designated ambassador to Israel, David M. Friedman, has said is a “high priority” for the administration.

Technically, the administration has until June to decide whether to renew a waiver, signed every six months by Obama and his predecessors, citing “national security” reasons for not moving the embassy. The move would have major international significance; Jerusalem is claimed by both Israelis and Palestinians as their capital, and its status has long been considered the subject of future negotiations between the two. No other country has its embassy in Jerusalem.

Asked three times when and if the move would happen, Spicer repeated that the administration was only in the “early stages” of making a decision. “If it was already a decision,” he said, “then we wouldn’t be going through a process.” The Israeli media has been rife with reports than an announcement on the move was imminent.

Meanwhile, Trump was meeting with a small group of union leaders and workers to promote his executive order canceling participating in the TPP.

“This is a group I know well,” the president said, noting that he had hired “thousands and thousands and thousands” of them over the years.

At the end of the day, Trump met with a bipartisan group of congressional leaders and declared it was the beginning of a “beautiful, beautiful relationship.”

As reporters were ushered out, Trump turned to business.

“We’re about to make a big deal,” he said, eliciting laughs around the table.

But Trump wasn’t ready to quite move past discussing the election.

He spent about 10 minutes of the meeting providing a blow-by-blow of election night, according to a person familiar with the discussion, and continued to insist that there were between 3 million to 5 million illegal votes, without which he would have won the popular vote.

Amy Goldstein, Abby Phillip and Ylan Q. Mui contributed to this report.