Border wall negotiations on Capitol Hill crumbled over the weekend, increasing the chances President Donald Trump declares a national emergency Friday, three sources close to the process tell The Daily Caller.

The negotiations stalled over a Democratic demand that detention bed funding for Immigration and Customs Enforcement (ICE) to house detained illegal immigrants be reduced in exchange for border wall funding. Lead Republican negotiator Sen. Richard Shelby told Fox News Sunday that the chances of a deal are “50/50,” after expressing optimism on Thursday.

An administration source directly involved in the process told the Caller that Trump began speaking more about declaring a national emergency Sunday after nearly a week of expressing optimism that the congressional talks could bear fruit. Trump also tweeted to that effect Sunday afternoon:

“President is on sound legal ground to declare a National Emergency. There have been 58 National Emergencies declared since the law was enacted in 1976, and 31 right now that are currently active, so this is hardly unprecedented.” Congressman @tommcclintock — Donald J. Trump (@realDonaldTrump) February 10, 2019

Acting White House Chief of Staff Mick Mulvaney said he “absolutely cannot” rule out a shutdown on Fox News Sunday, later saying on NBC News that Trump is “going to do whatever he legally can to secure the border.”

Trump has signaled to White House negotiators and Capitol Hill Republicans that he is willing to accept a $2 billion figure in border wall funding, two sources close to the process tell the Caller. Democrats, however, have made any acceptance of this figure contingent on an agreement to limit funding for ICE detention beds. (RELATED: Raid Leads To More Than 100 ICE Arrests In New York)

Democrats say that a cap on ICE detention beds will disincentivize the agency from detaining illegal aliens who have not committed crimes in the U.S.

“A cap on ICE detention beds will force the Trump administration to prioritize deportation for criminals and people who pose real security threats, not law-abiding immigrants who are contributing to our country,” Congressional negotiator Lucille Roybal-Allard said in a Sunday statement.

Republicans and ICE itself counter that putting a cap on the number of illegal aliens it is capable of detaining would in effect mean free rein for murderers and gang criminals convicted of felonies.

An administration source involved in the process expressed outrage at the demand to the Caller, noting that the Democratic lawmakers are essentially risking another government shutdown or a national emergency declaration to secure status for people in the country illegally.

“Illegals over Americans,” the source said to the Caller.

Trump also expressed outrage at the Democratic demand on Twitter Monday morning, saying:

The Democrats do not want us to detain, or send back, criminal aliens! This is a brand new demand. Crazy! — Donald J. Trump (@realDonaldTrump) February 11, 2019

Trump is likely to share his thoughts on the developments at a Monday evening rally in El Paso, Texas which is set to take place less than 1,000 feet from a border wall.