(CNN) -- US Immigration and Customs Enforcement plans to begin raids across the country Sunday to arrest thousands of family members who already have court orders to be removed, according to a US official.
The effort comes weeks after President Donald Trump had tweeted ICE's plans to conduct the raids, then delayed the operation after additional details became public.
The New York Times first reported on the raids, saying they are expected to take place in at least 10 cities, will occur "over multiple days" and will include "collateral" deportations in which "authorities might detain immigrants who happened to be on the scene, even though they were not targets of the raids."
Matthew Bourke, an ICE spokesman, said ICE will not comment on operational details and "ICE prioritizes the arrest and removal of unlawfully present aliens who pose a threat to national security, public safety and border security."
On Wednesday, acting US Citizenship and Immigration Services director Ken Cuccinelli said the ICE raids are "absolutely going to happen" following a delay from the President to see if Congress could work out a legislative solution on immigration.
"They're absolutely going to happen. There's approximately a million people in this country with removal orders. And of course that isn't what ICE will go after in this, but that's the pool of people who have been all the way through the due process chain," he told reporters at the White House.
ICE had planned to arrest and deport families with court-ordered removals in 10 cities in late June, according to a senior immigration official. The day before the raids were set to begin, Trump delayed them for two weeks, saying he would wait "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."
A week later at the G20 summit, Trump said his administration still planed to launch a series of ICE raids sometime after the end of that two week period, which would be after the July Fourth holiday.