WASHINGTON (AP) — Facing bipartisan pushback, President Donald Trump said Tuesday he's not looking to revive the much-criticized practice of separating migrant children from their families at the southern border. At the same time, he suggested the policy had worked to deter migrants from coming into the U.S.

Last summer the administration had separated more than 2,500 children from their families before international outrage forced Trump to halt the practice and a judge ordered them reunited.

"We're not looking to do that," Trump told reporters before meeting with Egypt's president at the White House. But he also noted: "Once you don't have it, that's why you see many more people coming. They're coming like it's a picnic, because let's go to Disneyland."

The potential reinstatement one of the most divisive practices by Trump was just one aspect of the upheaval evident at the Department of Homeland Security this week following the resignation of Kirstjen Nielsen. More leaders were likely to depart the agency in a shakeup orchestrated by the White House to address Trump's inability to stem border crossings.

Trump declared that he was "the one that stopped it" and said his predecessor, President Barack Obama, was the one who had separated children from their families. The administration is allowed to separate children under certain circumstances including the health and welfare of the child and a parent's criminal history; this is why children were separated under Obama.

At hearings across Capitol Hill, lawmakers grilled administration officials on whether the practice would resurface despite last year's outrage and evidence that separations were likely to cause lasting psychological effects on the children.

People familiar with immigration discussion said family separation is one of many suggestions that Trump and his aides were eyeing to tackle the problem of an ever-growing number of Central American families crossing into the U.S. The people were not authorized to speak publicly and spoke to The Associated Press on condition of anonymity.

A senior administration official who briefed reporters on condition of anonymity said it would move forward with a new regulation that would challenge a longstanding agreement limiting how long children can be detained in order to spark a fight that would eventually land in the Supreme Court.

They were also weighing a tougher standard to weigh initial asylum claims, a "binary choice" policy that would give migrant families the choice of remaining with their children in detention until their immigration cases are decided or separating from their children, and targeting remittance payments that Mexican national send home.

The person argued that DHS was a large and unwieldly civilian bureaucracy that requires leadership that can deal with career officials resistant to the president's agenda, including many who were responsible for implementing some of the very policies Trump seeks to roll back.

At the same time, Trump was talking to reporters, insisting he was not "cleaning house" at the agency despite a number of staff changes. He said his choice to be the department's new acting director, Kevin McAleenan, would do a "fantastic job," adding: "We're not doing anything very big as far as what we need: homeland security, that's exactly what we want."

Top Republicans in Congress expressed concern over vacancies at Homeland Security and cautioned Trump about more churn after the resignation of Nielsen.

Sen. Susan Collins, R-Maine, said Tuesday that having participated in creating the department more than a decade ago, she knows "these are vital positions."

Sen. Chuck Grassley, R-Iowa, made both a public and private plea to the White House not to dismiss career homeland security officials. He said he spoke to acting chief of staff Mick Mulvaney but would only know if Trump heard the message "if they don't get fired."

At a Senate Homeland Security Committee meeting on border issues, child welfare and border officials warned there wasn't room or capability to start separating children on a large scale again.

Children who cross the border alone are cared for by the Department of Health and Human Services, and most of the children are teenagers. But last summer, HHS started receiving babies and toddlers, and there was not enough space to house them, said Jonathan White, the career civil servant tasked by Health and Human Services with helping to reunify children.

"It also bears repeating, separating children from their parents entails significant risk of psychological harm. That is an undisputed scientific fact," White told senators. "We have made improvements to our tracking, but we do not have the capacity to receive that number of children, nor do we have any system that can manage the mass trauma."

Both Republican and Democratic leaders deplored the idea of separating families.

"I hope members of the administration are actually listening," said Sen. Ron Johnson, R- Wis., the committee chairman.

While Trump disputed any departmental upheaval, his outside allies launched a public campaign urging him to nominate former Kansas Secretary of State Kris Kobach to replace Nielsen. Kobach would almost certainly face an uphill battle to be confirmed by the Senate.

Meanwhile, a second conservative group pushed former Virginia Attorney General Ken Cuccinelli for the job. Both men's names also have been tossed about for a possible immigration czar who would coordinate immigration policy across various federal agencies.

Concerned legislators were also rallying Tuesday to defend Lee Francis Cissna, the director of U.S. Citizenship and Immigration Services, whose job was said to be in danger.

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Associated Press writers Kevin Freking, Lisa Mascaro and Darlene Superville in Washington and Nomaan Merchant in Houston contributed to this report.