President Trump on Wednesday began putting in place his plan to ratchet up immigration enforcement, following through on major campaign pledges by signing executive actions to build a border wall with Mexico and cut off funds to cities that do not report undocumented immigrants to federal authorities.

In an appearance at the Department of Homeland Security, Trump kicked off the rollout of a series of directives aimed at clamping down on the estimated 11 million immigrants living illegally in the United States and potentially tightening restrictions on those trying to come to the country through legal channels.

Aides said more directives could come later this week, including new restrictions on refugees and immigrants from ­Muslim-majority countries over concerns about terrorism.

The presidential directives signed Wednesday aim to create more detention centers, add thousands of Border Patrol agents and withhold federal funds from what are known as sanctuary cities, which do not comply with federal immigration laws. One order calls for the “immediate construction of a physical wall.”

[Read Trump’s executive order on the border and immigration]

“We are going to restore the rule of law in the United States,” Trump told a crowd of DHS employees, who applauded several times during the president’s remarks. “Beginning today, the United States gets control of its borders.”

The construction of a wall along the southern U.S. border was Trump’s chief campaign promise as he blamed illegal immigration for constricting the U.S. job market for Americans and adding to national security concerns.

But his moves prompted an immediate backlash from congressional Democrats and immigrant rights groups, which accused the president of hyperbole to whip up fear in the electorate at the expense of immigrants and refugees. Protesters gathered outside the White House within hours of Trump’s announcement.

“The hateful, xenophobic, ­anti-immigrant and anti-Muslim rhetoric that was a hallmark of the Trump campaign is starting to become a reality,” said Marielena Hincapie, executive director of the National Immigration Law Center. “Chaos and destruction will be the outcome.”

Though Trump promised that construction of the border wall would begin within months, it remained unclear how his directive would accelerate the project or pay for the added enforcement personnel. Federal funds would have to be appropriated by Congress, and construction industry analysts have said the total costs of a barrier along the southern U.S. border with Mexico could approach $20 billion.

Trump’s directives also call for an additional 5,000 Border Patrol agents and 10,000 immigration officials. Administration officials have said they are discussing funding options with GOP lawmakers.

In an interview with ABC News, Trump said construction would begin “as soon as we can physically do it. I would say in months.” He has said the project would start with U.S. tax dollars in order to begin quickly, but he reiterated his promise that the United States would be reimbursed by the Mexican government.

1 of 25 Full Screen Autoplay Close Skip Ad × What it looks like along the border fence between the U.S. and Mexico View Photos With a border nearly 2,000 miles long between the United States and Mexico, about 650 miles of fencing is already in place along parts of Texas, New Mexico, Arizona and California. Caption About 650 miles of fencing is already in place in parts of Texas, New Mexico, Arizona and California, but the border is nearly 2,000 miles long. Jan. 26, 2017 A photo taken by a drone shows the fencing on the border on the outskirts of Tijuana, Mexico. Mario Vazquez/AFP/Getty Images Buy Photo Wait 1 second to continue.

Trump is scheduled to welcome Mexican President Enrique Peña Nieto — who told him during the campaign that his administration would not pay for a wall — for a bilateral meeting at the White House next week. Mexicans called on Peña Nieto to cancel the summit.

[Mexicans want their president to cancel Washington visit after Trump touts his wall]

“We’ll be reimbursed at a later date from whatever transaction we make from Mexico,” Trump said in the television interview. “I’m just telling you there will be a payment. It will be in a form, perhaps a complicated form.”

Peña Nieto, in a televised address Wednesday night, said “I regret and reject” Trump’s decision to build the wall and added: “I have said time and again, Mexico will not pay for any wall.” He also said that the 50 Mexican consulates across the United States will “turn into places to defend rights of Mexicans. Where a Mexican needs legal help, they will be there.”

Trump also scoffed at concerns that his proposed actions could further fuel hatred of the United States and motivate Islamic State terrorists. “Anger? There’s plenty of anger right now. How can you have more?” Trump told ABC’s David Muir.

Congressional Republicans cheered Trump’s announcement as a long overdue focus on border security, but Democrats warned that it would torpedo efforts to achieve bipartisan consensus on a comprehensive immigration reform bill that eluded the administrations of Republican George W. Bush and Democrat Barack Obama.

Democrats have called for stricter enforcement to be coupled with a path to citizenship for undocumented immigrants who have not committed additional crimes.

“Turning away legitimate asylum seekers at the border, and requiring mandatory detention of families and children, will do nothing to make America safer,” Sen. Benjamin L. Cardin (D-Md.) said.

Trump kicked off his campaign with a fiery speech in 2015 during which he referred to illegal immigrants from Mexico as criminals and rapists and pledged to make stronger enforcement a centerpiece of his agenda.

The strategy defied a growing consensus among establishment Republicans that the GOP must pursue comprehensive reform, including a path to citizenship, in order to make inroads with the fast-growing Latino population. After a comprehensive reform bill died in Congress in 2014, Obama moved to focus his administration’s enforcement efforts on those who had committed felonies or had ties to terrorism.

During his visit to DHS, Trump thanked the Border Patrol agents and immigration officers who, he claimed, “unanimously endorsed me” — though it was the unions representing the employees, whose leadership had chafed at Obama’s policies, that had backed his candidacy.

Trump told the employees that retired Marine Gen. John F. Kelly, sworn in last week as the new homeland security secretary, would be charged with carrying out his directives.

“He’s a rough, tough guy, but he’s also got a good heart,” Trump said.

Trump also recognized members of the Remembrance Project, a Texas-based advocacy group that represents the families of victims who were killed by people not legally in the country. Trump was frequently joined by the parents of these victims at campaign rallies, especially those in states close to the southern border.

On Wednesday, he thanked them for having “kept the flame of justice alive.”

“Your children will not have lost their lives for no reason,” Trump said.

The executive actions include measures to bolster enforcement inside the United States, suggesting that Trump aims to make good on promises to boost workplace raids and ramp up deportations.

The actions include a directive to Kelly to examine ways to limit federal funding to sanctuary cities — including Washington, Los Angeles and San Francisco — that were a focus of attacks from Trump on the campaign trail.

And White House press secretary Sean Spicer said the Trump administration would resume the Secure Communities program that granted greater immigration enforcement powers to local authorities — a program that was shut down by the Obama administration over concerns it had led to abuse.

Yet Trump on Wednesday did not sign any orders overturning the Obama administration’s Deferred Action for Childhood Arrivals program, which has allowed more than 700,000 younger immigrants brought to the country illegally as children to apply for two-year work visas.

During the campaign, Trump had promised to end DACA, which has been enormously popular among the immigrant rights community.

“The president understands the magnitude of this problem,” Spicer said of DACA. “He’s a family man. He has a huge heart.”

Trump will work through it “in a very humane way,” the spokesman added.

Jenna Johnson contributed to this report.

Read more:

What it will take for President Trump to deport millions and build the wall

What exactly are ‘sanctuary cities’ in immigration policy?

How sanctuary cities work and what might happen to them under Trump