Donald Trump announced plans to delay a national deportation scheme aimed at removing people living illegally in the US.
The US president said the countrywide sweep would be on hold for two weeks while in order for lawmakers to work out border solutions.
His announcement on Twitter came after House Speaker Nancy Pelosi called Mr Trump asking him to call off the operation.
Administration officials at the Immigration and Customs Enforcement were concerned that details leaked to the media could jeopardize its agents.
President Trump said: "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!"
Lawmakers are weighing up whether to give $4.6 billion in emergency funding to help border agencies struggling to deal with illegal immigration over their borders.
Following Trump's announcement of the delay, Ms Pelosi said: "Mr President, delay is welcome. Time is needed for comprehensive immigration reform. Families belong together."
Despite Mr Trump's tough rhetoric, the number of people illegally crossing from Mexico into the US has ridden dramatically under Mr Trump's presidency.
Trump tweeted Saturday morning hinting the operation was still on, saying the immigrants "that Ice (sic) will apprehend have already been ordered to be deported," he wrote. "This means that they have run from the law and run from the courts."
The planned operation was heavily criticized by Democratic lawmakers as cruel, and many local mayors said they would refuse to cooperate with ICE.
Another complication is that ICE needs travel paperwork from a home country to deport someone, so immigrants often end up detained at least temporarily waiting for a flight.
ICE was reserving hotel rooms in for families in the event the operation went off as planned Sunday.
The adult population of detainees was 53,141 as of June 8, though the agency is only budgeted for 45,000. There were 1,662 in family detention, also at capacity, and one of the family detention centers is currently housing single adults.