After defending his plan Saturday to deport undocumented immigrants, President Donald Trump tweeted hours later that he “delayed the Illegal Immigration Removal Process (Deportation) for two weeks to see if the Democrats and Republicans can get together and work out a solution to the Asylum and Loophole problems at the Southern Border.”

“If not, Deportations start!” he warned.

At the request of Democrats, I have delayed the Illegal Immigration Removal Process (Deportation) for two weeks to see if the Democrats and Republicans can get together and work out a solution to the Asylum and Loophole problems at the Southern Border. If not, Deportations start! — Donald J. Trump (@realDonaldTrump) June 22, 2019

The tweet comes after immigration advocates and officials in some major U.S. cities condemned plans for Immigration and Customs Enforcement raids aimed at rounding up thousands of families facing deportation orders, which were to begin Sunday.

Speaking to reporters at the White House lawn before departing for Camp David on Saturday morning, Trump said that “exportation raids are groups of very, very good law enforcement people going by the law, going by our court system, taking people out who came in illegally and out legally.”

He anticipated that “some cities are going to fight it” but claimed that the resistance was from "sanctuary cities," which, along with some states, have policies aimed at protecting undocumented immigrants from deportation.

But hours later, he tweeted the delay.

The Washington Post reported that Immigration and Customs Enforcement planned to target about 2,000 families who had received deportation orders in up to 10 cities — including Miami, Los Angeles, Chicago and Houston — starting Sunday, even though the president originally claimed Monday that “millions” would be removed.

The reports that ICE planned to conduct large-scale enforcement actions have prompted pushback from Democratic mayors from Los Angeles; Chicago; San Francisco; Newark, New Jersey; and New York, who have condemned the actions and launched efforts to aid residents. (Several of these cities identify themselves as sanctuary cities.) A handful of major metropolitan police departments have also announced they will not cooperate with federal immigration authorities.

In addition to these mayors, civil and immigration rights organizations such as the American Civil Liberties Union and National Immigration Law Center have been publicizing the rights that undocumented people have in the event they are stopped or visited by law enforcement.

While cities must comply with federal law enforcement, their leaders can use their platforms to educate citizens about what to do if federal law enforcement approaches them, said David W. Leopold, an immigration attorney and former president of the American Immigration Lawyers Association.

“Nobody’s trying to stand in the way of law enforcement, but what mayors can do is make sure that their citizens, their constituents know their rights,” he said.

For police departments, cooperation with immigration officials could weaken communities’ trust in police, Leopold said. He also added that local authorities may not be trained in the nuances of immigration law and the rights that undocumented people have.

“I think it’s a wise move for a mayor or a chief of police to be extremely cautious and stay away from ICE enforcement operations,” he said. “Let ICE do their job; they’re the ones who are trained.”

Leaders and law enforcement in California’s major cities have taken some of the strongest stances against the Trump administration’s planned action.

Oakland Mayor Libby Schaaf, a Democrat, who sparred with Trump over her city’s sanctuary city policy in April, said Friday that while she did not have specific information about “raids in this community,” she urged residents to “not panic.” Earlier in the week, she called the president’s behavior “ruthless and reckless” during an appearance on CNN and appeared to imply in a tweet that the city would take action if officials received “credible information” about planned immigration enforcement action. Schaaf previously alerted residents about potential ICE raids in 2018, drawing Trump’s ire.

Schaaf’s counterpart across the bay, San Francisco Mayor London Breed, also a Democrat, pledged in a statement, “We will continue to remain vigilant and offer services for all immigrants through the Office of Civic Engagement and Immigrant Affairs,” ABC 7 reported.

The San Francisco Police Department said “it does not and will not” cooperate with ICE or Customs and Border Protection officials to carry out deportations.

Another San Francisco Bay area leader, House Speaker Nancy Pelosi, D-Calif., in a statement Saturday described the planned raids as “heartless” and said religious leaders should “call upon the President to stop this brutal action which will tear families apart and inject terror into our communities.”

The Los Angeles Police Department confirmed that it was aware of the raids and would not be participating. Mayor Eric Garcetti, a Democrat, said on Twitter that his administration was “doing everything we can to provide immigrant families with info and support ahead of the announced ICE deportation sweeps.”

Similarly, in Chicago, Mayor Lori Lightfoot, a Democrat, announced that the city’s police department had revoked U.S. Immigration and Customs Enforcement access to some of its databases and that Chicago police would not “cooperate with or facilitate any ICE enforcement actions.”

In a tweet addressed to the president, New York Mayor Bill de Blasio said that residents “won’t be divided by a sick plot to tear families apart and force immigrants into the shadows,” while the mayor of nearby Newark, Ras J. Baraka, a Democrat, joined other urban mayors from around he state in calling the raids “racist, bigoted, and inhumane.”

“This outrageous tearing of families apart and causing fear in communities across America is clearly a political stunt, coming on the heels of Trump’s kickoff of his reelection campaign,” their statement read. “We stand with our undocumented immigrant communities and are committed to protecting them, regardless of the actions of President Trump and his administration.”

However, not all cities are pushing back against the Trump administration. Miami is said to be one of the cities targeted in ICE’s upcoming raid, but Republican Florida Gov. Ron DeSantis signed a bill last week that prohibits sanctuary cities in the state and mandates that local officials must cooperate with federal immigration forces.

The Washington Post reported this week that the Justice Department, which runs the immigration courts, was aware of at least 12,780 removal orders issued to “family units” from Sept. 24 through Friday.

On June 4, ICE’s new chief, Mark Morgan, said that the agency was developing plans to target families that had not heeded orders to leave the United States.

“Our next challenge is going to be interior enforcement,” Morgan said at the time. “We will be going after individuals who have gone through due process and who have received final orders of deportation,” and he confirmed that plan would include families. He pledged that immigration officials would treat the families “with compassion and humanity.”

Colby Itkowitz contributed to this report.