The Trump administration on Wednesday requested an extra $4.5 billion to address the surge of migrants at the U.S. southern border, in a move that could trigger a fresh round of criticism over President Donald Trump’s immigration policies.

The supplemental request stops short of seeking additional money for a border wall, which Democrats have staunchly opposed. But Democrats are sure to press for changes to immigration policy they consider too harsh.

[Why Democrats aren’t rushing to change immigration laws]

In a statement, House Appropriations Chairwoman Nita M. Lowey, D-N.Y., said “much of” the new White House request would “double down on cruel and ill-conceived policies, including bailing out [Immigration and Customs Enforcement] for overspending on detention beds and expanding family detention.” She pledged to give the request a full review, however, and look for possible areas of common ground.

The border aid request is also further complicating a package disaster relief appropriations to respond to hurricanes, flooding and other calamities which hit states from California to Iowa to Florida over the past year.

Senate Republicans and Democrats have been struggling to agree on a disaster bill, with different versions ranging between $13.5 billion and $17.2 billion, hung up chiefly due to a dispute over money for Puerto Rico, which is still rebuilding after 2017′s Hurricane Maria.

The disaster aid package is an obvious vehicle to carry additional funds to respond to the border situation, which may be what Trump needs in order to sign a bill that has the Puerto Rico money Democrats want. But Democrats aren’t sold on the border package Trump wants, which could cause further delays in getting a bill to the president’s desk.

[Pentagon wants Congress to replenish funds Trump taps for border wall]

“We’re a ‘no’” on the border package, said Sen. Brian Schatz, D-Hawaii, ranking member on the Military Construction-VA Appropriations Subcommittee. “But we’re still going to have to come to a bipartisan compromise on disaster aid.”

Sen. David Perdue, R-Ga., who has been pressing for swift movement on a disaster relief bill to help his state’s crop growers hit hard by Hurricane Michael and severe cold two years ago, said the border request was now the biggest holdup. “I really don’t think it’s Puerto Rico,” he said.

Senate Appropriations Chairman Richard C. Shelby, R-Ala., said talks on the broader supplemental package remain “stalled,” but was tight-lipped on how the border request would impact disaster relief negotiations. “Well, we’ll have to evaluate all that, but we’ve got time,” he said.

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There may not be that much time, however, according to the Trump administration.

The new White House border request includes $3.3 billion for humanitarian aid, mainly $2.8 billion for the Department of Health and Human Services to provide shelter and other welfare services for unaccompanied minors, including an additional 23,600 beds. Without additional funding, HHS is likely to run out of money in June and be forced to divert money from other critical programs, according to a letter from acting Office of Management and Budget chief Russell Vought.

The request provides $1.1 billion for the Department of Homeland Security, including $391 million for humanitarian assistance and temporary migrant processing facilities, along with $530 million for personnel costs and increased transportation and housing expenses. Part of that is $342 million to expand ICE detention bed capacity — what Lowey referred to as “bailing out” ICE — which would support an increase in the average daily population of roughly 8,500 above what is provided in the fiscal 2019 omnibus package (PL 116-6).

There’s also $178 million for DHS operations and support costs, including information technology and upgrades.

A separate fact sheet accompanying the request says DHS will run out of resources to deal with the surge of migrants before the end of the fiscal year without action from Congress.

In addition, there is $377 million for the Defense Department to provide logistical support, and $155 million for the Justice Department to “accommodate significant increases in detained populations, including criminal aliens.”

Trump has sought to toughen U.S. asylum regulations and proposed sending migrants apprehended at the border to “sanctuary cities” within the U.S. that are often run by Democrats. He has repeatedly threatened to “shut down” the border, or at least parts of it, if Mexico doesn’t take steps to stop migrants.

“Addressing the humanitarian crises, in the short term, is in part a resource challenge,” said Rep. Lucille Roybal-Allard, D-Calif., chairwoman of the House Homeland Security Appropriations Subcommittee, at a hearing Tuesday with acting Homeland Security Secretary Kevin McAleenan. “But it is also a challenge that requires a commitment by your department to respect the rights of immigrants and to treat them humanely.”

Democrats have complained about administration efforts to restrict asylum applications and detention policies that they say can lead to prolonged government custody of unaccompanied children. A senior administration official, speaking to reporters in a conference call Wednesday, said a discussion of policy changes could occur as the emergency funding request gets considered.

“We’re definitely open to having that conversation with Congress,” the official said.

The regular Trump budget request, submitted in March, already included $192 million to hire 750 more Border Patrol agents and 273 Customs and Border Protection officers. It also included $523 million for humanitarian relief.

The department has sought more resources to cope with a dramatic increase in the number of families and unaccompanied minors crossing the border, mostly fleeing the violence and poverty in El Salvador, Honduras and Guatemala. More than 100,000 such migrants were apprehended at the border in March alone.

Democrats were already peeved at Trump for declaring a national emergency to build a border wall with money that Congress never approved. The emergency declaration, which faces court challenges, would allow Trump to tap up to $3.6 billion in military construction funding and use it at the southern border instead.

House Democrats have included riders intended to block such a move in disaster aid legislation (HR 2157) expected on the House floor next week as well as a draft fiscal 2020 Military Construction-VA spending bill House appropriators will consider in subcommittee later on Wednesday.

The page for the draft fiscal 2020 House Military Construction-VA spending bill is here.

Paul M. Krawzak and Kellie Mejdrich contributed to this report.