WASHINGTON - The partial U.S. government shutdown hit its 10th day Monday, with no end in sight, as federal spending negotiations remain stalled between President Donald Trump and lawmakers heading into 2019.

Trump continues to demand billions of dollars in federal spending for wall construction along the U.S.-Mexico border. Democratic lawmakers back a modest increase in overall border security funding but resolutely oppose a wall. Spending authority for one fourth of the U.S. government expired on December 22.

FILE - The US Capitol is seen during a government FILE - The U.S. Capitol is seen closed off by a road barrier, during a partial government shutdown in Washington, Dec. 27, 2018. FILE - The U.S. Capitol is seen closed off by a road barrier, during a partial government shutdown in Washington, Dec. 27, 2018.

White House officials said talks to resolve the impasse have broken off.

Trump on Sunday tweeted that Democrats “left town and are not concerned about the safety and security of Americans!”

Great work by my Administration over the holidays to save Coast Guard pay during this #SchumerShutdown. No thanks to the Democrats who left town and are not concerned about the safety and security of Americans! — Donald J. Trump (@realDonaldTrump) December 30, 2018

Democrats scoffed at the accusation.

“This is the same president who repeatedly promised the American people that Mexico would pay for the wall that he plans to build,” New York Rep. Hakeem Jeffries said on ABC’s This Week program. “Now he’s trying to extract $5 billion from the American taxpayer to pay for something that clearly would be ineffective.”

“President Trump has taken hundreds of thousands of federal employees' pay hostage in a last ditch effort to fulfill a campaign promise,” the Senate’s No. 2 Democrat, Dick Durbin of Illinois, tweeted. “Building a wall from sea to shining sea won't make us safer or stop drugs from coming into our country.”

Border wall prototypes stand in San Diego near the FILE - Border wall prototypes stand in San Diego near the U.S.-Mexico border, as seen from Tijuana, Mexico, Dec. 22, 2018. FILE - Border wall prototypes stand in San Diego near the U.S.-Mexico border, as seen from Tijuana, Mexico, Dec. 22, 2018.

In a series of tweets on Friday, Trump again threatened to close the entire U.S.-Mexico border and cut aid to Honduras, Guatemala and El Salvador if Congress failed to give him money to fund the wall. He also asked for changes in what he said was the United States’ "ridiculous immigration laws.”

Closing the U.S.-Mexican border would mean disrupting a $1.68 billion-a-day trade relationship between the two countries. In addition, immigrant advocates have called any move to seal the border "disgraceful."

In a tweet Saturday, Trump linked Democrats’ "pathetic immigration policies” with the deaths of two Guatemalan children while in U.S. custody.

His comments, the first to reference the children's deaths, came the same day Department of Homeland Security Secretary Kirstjen Nielsen was finishing a two-day visit to the southern U.S. border, where she said in a statement, "The system is clearly overwhelmed and we must work together to address this humanitarian crisis."

Migrants wait in line for food at a camp containin FILE - Migrants wait in line for food at a camp housing hundreds of people who arrived at the U.S. border from Central America with the intention of applying for asylum in the U.S., in Tijuana, Mexico, Dec. 12, 2018. FILE - Migrants wait in line for food at a camp housing hundreds of people who arrived at the U.S. border from Central America with the intention of applying for asylum in the U.S., in Tijuana, Mexico, Dec. 12, 2018.

Trump has declined to comment on whether he might accept less than $5 billion for wall funding. When asked Wednesday how long he thought the shutdown would last, Trump told reporters, "Whatever it takes."

Out of a workforce of about 2.1 million federal employees, more than 800,000 have been furloughed without pay. About 420,000 of those furloughed employees are still being required to work without pay.

Democrats have blamed Trump for "plunging the country into chaos" and have noted that, weeks ago, Trump said he would be "proud" to "own" a shutdown over border wall funding.

The Republican Party controls the White House, as well as both chambers of Congress. On Thursday, however, a new Congress, with a Democrat-controlled House, will be seated.