WASHINGTON (AP) — The White House is threatening to veto a $4.5 billion House bill aimed at improving the treatment of migrant families detained after crossing the U.S. southern border, saying the measure would hamstring the administration’s border security efforts and raising fresh questions about the legislation’s fate.

The warning came as Hispanic and liberal Democrats press House leaders to add provisions to the legislation strengthening protections for migrant children, changes that might make the measure even less palatable to President Donald Trump. Though revisions are possible, House leaders are still hoping for approval as early as Tuesday.

The Senate planned to vote this week on similar legislation that has bipartisan backing, but many House Democrats say the Senate version’s provisions aimed at helping migrant children are not strong enough. House Democrats seeking changes met late Monday with Speaker Nancy Pelosi, D-Calif.

“Right now, the goal is really to stop — one death is just too much,” said Rep. Adriano Espaillat, D-N.Y., as he left that meeting.

Many children detained entering the U.S. from Mexico have been held under harsh conditions, and Customs and Border Protection Chief Operating Officer John Sanders told The Associated Press last week that children have died after being in the agency’s care. He said Border Patrol stations are holding 15,000 people — more than triple their maximum capacity of 4,000.

Congress plans to leave Washington in a few days for a weeklong July 4 recess. While lawmakers don’t want to depart without acting on the legislation for fear of being accused of not responding to humanitarian problems at the border, it seems unlikely that Congress would have time to send a House-Senate compromise to Trump by week’s end.

In a letter Monday threatening the veto, White House officials told lawmakers they objected that the House package lacked money for beds the federal Immigration and Customs Enforcement agency needs to let it detain more migrants. Officials also complained in the letter that the bill had no money to toughen border security, including funds for building Trump’s proposed border wall.

“Because this bill does not provide adequate funding to meet the current crisis, and because it contains partisan provisions designed to hamstring the Administration’s border enforcement efforts, the Administration opposes its passage,” the letter said.

Several Democrats said some language they were seeking could end up in separate legislation. Several said changes might include provisions aimed at ensuring that detained children are treated humanely.

“We’ve got lives at stake,” said Rep. Tony Cardenas, D-Calif. He said the U.S. has been “the gold standard” for treating refugees fleeing dangerous countries, “and I don’t think we should compromise that at all.”

The meeting may have helped ease Democratic complaints. Rep. Alexandria Ocasio-Cortez, D-N.Y., told reporters before the meeting that she would oppose the bill but left the door open afterward, saying, “I oppose the situation we’re in, but my main goal is to keep kids from dying.”

Much of the legislation’s money would help care for migrants at a time when federal officials say their agencies have been overwhelmed by the influx of migrants and are running out of funds.

The back-and-forth on the spending measure came as Congress’ top Democrats criticized Trump for threatening coast-to-coast deportations of migrants.

Over the weekend, Trump tweeted that he would give Congress two weeks to solve “the Asylum and Loopholes problems” along the border with Mexico. “If not, Deportations start!” he tweeted.

The president had earlier warned that there would soon be a nationwide sweep aimed at “millions” of people living illegally in the U.S., including families. The sweeps were supposed to begin Sunday, but Trump said he postponed them.

Pelosi, D-Calif., said the threatened raids were “appalling” when she was asked about them at an immigration event Monday in Queens, New York.

“It is outside the circle of civilized human behavior, just kicking down doors, splitting up families and the rest of that in addition to the injustices that are happening at the border,” she said.

On the Senate floor, Minority Leader Chuck Schumer, D-N.Y., described Trump’s “chilling, nasty, obnoxious threats” and said the president “seems far more comfortable terrorizing immigrant families” than addressing immigration problems.

“I mean, my God, to threaten separating children from their parents as a bargaining chip? That’s the very definition of callousness,” Schumer said.

It is not clear exactly what Trump, who has started his 2020 re-election bid, means regarding asylum and loophole changes. He’s long been trying to restrict the numbers of people being allowed to enter the U.S. after claiming asylum and impose other restrictions, a path he’s followed since he began his quest for president years ago. His threatened deportations came as authorities have been overwhelmed by a huge increase of migrants crossing the border into the U.S. in recent months.

For years, Democrats and Republicans have unable to find middle ground on immigration that can pass Congress. It seems unlikely they will suddenly find a solution within two weeks.

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AP Congressional Correspondent Lisa Mascaro and Associated Press writer Colleen Long contributed to this report.