FILE - President Donald Trump speaks during a meeting in the Oval Office of the White House in Washington, Jan. 31, 2019.
FILE - President Donald Trump speaks during a meeting in the Oval Office of the White House in Washington, Jan. 31, 2019.

WASHINGTON - U.S. President Donald Trump blamed opposition Democrats on Monday for the stalled talks over immigration policies as the White House as lawmakers struggle to avert another partial government shutdown.

"The Democrats do not want us to detain, or send back, criminal aliens!" Trump said on Twitter.  "This is a brand new demand. Crazy!"

While the dispute initially centered on Trump's demand for $5.7 billion to build a wall along part of the U.S.-Mexican border, the negotiations have foundered on a Democratic effort to limit the number of undocumented immigrants apprehended within the United States, not at the border, who can be detained by U.S. immigration authorities.

Democrats are trying to curb the Trump administration's aggressive detention tactics.  They want to cap the number of detainees at 16,500, about the number who were held in the last years of the administration of Trump's predecessor, former president Barack Obama, although the number has risen under Trump.

Republicans are hoping to exclude several types of undocumented immigrants from the cap, including people charged or convicted of violent crimes as well as those committing misdemeanor drug offenses.

Migrants traveling with children walk up a hill t
FILE - Migrants traveling with children walk up a hill to a waiting U.S. Border Patrol agent just inside San Ysidro, California, after climbing over the border wall from Playas de Tijuana, Mexico, Dec. 3, 2018.

A cap on the number of beds available for detained immigrants would force the Trump administration "to prioritize deportations for criminals and people who pose real security threats, not law-abiding citizens who are contributing to our country," said Congresswoman Lucille Roybal-Allard, a California Democrat who is among the 17 lawmakers on a negotiating panel trying to reach agreement on border security funding.

The White House and lawmakers are facing a Friday deadline, when funding runs out again for about a quarter of government operations, to avert a new closure three weeks after a record 35-day shutdown was ended Jan. 25.

Democrats have offered some funding - perhaps about $2 billion - for Trump's border wall, far less than he wants.

The stalled talks come as Trump is set to travel to the border at El Paso, Texas, for a rally Monday to focus on the wall he says would thwart people from illegally entering the United States from Mexico.

El Paso's former congressman, Beto O'Rourke, who is considering a possible run for the Democratic nomination in the 2020 presidential race, will be among those leading a march in opposition to Trump's wall demand.

In this Tuesday, Jan. 22, 2019, photo, a new barri
FILE - A new barrier is built along the Texas-Mexico border near downtown El Paso, Jan. 22, 2019. Such barriers have been a part of El Paso for decades and are currently being expanded.

Several lawmakers said late last week they were close to reaching a deal, even as it remained unclear what Trump would agree to, but over the weekend they said the talks have reached an impasse.

On Sunday, Sen. Richard Shelby of Alabama, the lead Republican on the 17-member congressional border security panel, told Fox News, "I think the talks are stalled right now.  I'm not confident we're going to get there."

Acting White House Chief of Staff Mick Mulvaney told NBC News another shutdown "absolutely cannot" be ruled out.  He said whether lawmakers are close to reaching a deal on border security funding "depends on who you listen to."

Mulvaney added, "The president really does believe that there is a national security crisis and a humanitarian crisis at the border and he will do something about it.  He is going to do whatever he legally can to secure that border."

He said if Trump does not win approval for as much money as he wants, he is likely to say, "I'll go find the money someplace else," by tapping other government funds, a move sure to draw a legal challenge from Democrats.

When the five-week closure ended last month, the bipartisan border security group was created to hammer out details of what border security operations would be funded and how much money would go toward Trump's demand for a wall, perhaps his most popular pledge from his successful 2016 campaign for the White House.

Democrats initially offered no funding for a wall, but now lawmakers familiar with the negotiations say Trump's opponents appear ready to agree to some border barrier funding, along with provisions for heightened controls at ports of entry to thwart drug smuggling and increased use of drones and other technology to try to halt illegal entry into the country.

Lawmakers have often said since the shutdown ended that a second closure would be prevented, but Trump has refused to rule it out if he does not like the border security agreement they present him.

He has not publicly stated what level of funding he would accept as a compromise to build a barrier along a relatively small portion of the 3,200-kilometer U.S.-Mexican border.