Immigrant advocates were bracing Thursday for a massive sweep of arrests and detentions amid reports that a roundup in at least 10 major cities could begin this weekend.

ICE officials would neither confirm nor deny a report Thursday in The New York Times, citing multiple administration officials the newspaper did not name, that the sweep would begin Sunday. President Donald Trump said last week that the Immigration and Customs Enforcement would begin a major sweep "soon."

"No one arrested in the immigration raids should be deported without a fair day in court," the American Immigration Council tweeted. "We are recruiting and training immigration attorneys from around the country to ensure this happens."

UnidosUS tweeted a list of don'ts and dos for immigrants – don't open doors, say anything to ICE agents, or sign anything, they said; do take pictures and get a lawyer.

"As the threat of ICE raids brings fear to our communities, it is important that you know your rights," the tweet said.

Speaking outside the White House on Wednesday, U.S. Citizenship and Immigration Services acting director Ken Cuccinelli declined to say when any raids would begin, but vowed that they were coming.

“They’re absolutely going to happen,” Cuccinelli said, adding that there are "approximately a million people in this country with removal orders. Of course that isn’t what ICE would go after in this. But that’s the pool of people who’ve been all the way through the due process chain.”

House Speaker Nancy Pelosi on Thursday decried the upcoming raids as immoral actions taken to “terrorize children and tear families apart.”

During a press conference at the Capitol, she stressed that a deportation order is not the same as a search warrant, and urged immigrants to learn their rights before allowing ICE to enter their homes.

“If ICE agents do not have a warrant signed by a judge, a person may refuse to open the door and let them in,” she said.

The Times said the sweep would target more than 2,000 immigrants facing deportation orders who remain in the country illegally. The sources told the Times that ICE planned to keep family members together at family detention facilities whenever possible.

Trump said two weeks ago that he would delay nationwide raids for two weeks to give Congress time to develop an immigration plan. Trump's hard line on immigration has been a recurring theme in his presidency and is expected to take center stage in his 2020 reelection bid.

ICE spokesman Matthew Bourke, in a statement emailed Thursday to USA TODAY, said ICE cannot provide details on coming raids for security reasons. ICE has consistently maintained that its focus is on people with criminal records but that anyone found to be in the U.S. illegally would face detainment.

"Ninety percent of aliens arrested by ICE’s Enforcement and Removal Operations component in FY2018 had either a criminal conviction, pending criminal charge, were an ICE fugitive or illegally reentered the country after previously being removed," Bourke said.

That is true, but in 2018 about 66% of people arrested by ICE had been convicted of a crime in the U.S. — a sharp drop from the final years of the Obama administration, which targeted undocumented immigrants with criminal records.

ICE officials previously have said they plan to target new arrivals in an effort to stem a surge of Central American families arriving through Mexico. That surge showed some decline in June, when total border arrests fell 29% according to numbers released by Customs and Border Protection. But the decline came after May totals — more than 140,000 arrests — that were the highest since 2006.

The Trump administration credits its escalating series of threats and new policies for the slowdown, although border crossing traditionally declines in the heat of summer.

"This is not a 'rule of law' operation," Ali Noorani, executive director of the National Immigration Forum, tweeted Thursday. "The goal is to terrorize immigrant communities so immigrants do not seek protection in the US."

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A government report released last week found that migrants were being held in overcrowded conditions described as “a ticking time bomb." In one room at Customs and Border Protection’s Fort Brown station near the U.S-Mexico border in Texas, 51 women were in a cell with a capacity for 40 juveniles, according to the report from the Department of Homeland Security’s inspector general’s office. In another cell, 71 men were in a cell designated for 41, the report said.

Trump was dismissive of the report, saying the facilities he visited were clean and well run.

“I think they do a great job with those facilities,” Trump said.

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