Chances for a partial shutdown of the U.S. government by the end of this week grew Sunday due to outrage over federal immigration agents fatally shooting Alex Pretti in Minnesota, the second such incident this month.
A growing chorus of Democratic senators warned that they will not vote for a massive $1.2 trillion package to fund federal government operations if it includes appropriations for the Department of Homeland Security, which oversees immigration enforcement efforts.
On Sunday, a Senate GOP spokesperson told CNBC that Republicans will not remove the DHS funding portion, despite that warning.
"Government funding expires at the end of the week, and Republicans are determined to not have another government shutdown," the spokesperson said.
"We will move forward as planned and hope Democrats can find a path forward to join us," the spokesperson said.
The House of Representatives on Thursday approved the funding package.
Without Senate approval of the deal by Friday, the federal government will begin a partial shutdown.
The funding package needs 60 votes to overcome the filibuster and pass the Senate.
Republicans hold a 53-47 vote majority in the Senate, meaning Democratic support will be needed to pass the measure.
The deadly shooting of Pretti, a 37-year-old ICU nurse who was a U.S. citizen, in Minneapolis on Saturday morning ignited already simmering concern among members of the Democratic caucuses in Congress about funding DHS.
Democrats already were angry about the fatal shooting of Minneapolis resident Renee Good by an Immigration and Customs Enforcement, or ICE, officer in that city on Jan. 7.
"Senate Democrats will not allow the current DHS funding bill to move forward," Senate Minority Leader Chuck Schumer, D-N.Y., said in a statement Sunday.
"Senate Republicans have seen the same horrific footage that all Americans have watched of the blatant abuses of Americans by ICE in Minnesota," Schumer said.
"The appalling murders of Renee Good and Alex Pretti on the streets of Minneapolis must lead Republicans to join Democrats in overhauling ICE and CBP to protect the public," he said. "People should be safe from abuse by their own government."
Sen. Angus King of Maine told CBS' "Face the Nation" on Sunday, "I can't vote for a bill that includes ICE funding under these circumstances."
"Take up DHS by itself, let's have an honest negotiation, put some guardrails on what's going on, some accountability, and that would solve this problem," said King, one of two independents who caucus with Democrats.
"We don't have to have a shutdown," he said.
King played a key role in ending last year's 43-day shutdown. He voted repeatedly to open the government during the last shutdown as his Democratic colleagues pushed for an extension of Obamacare subsidies.
Members of the House, which went into a pre-scheduled recess after passing the bill, would have to return to approve any changes the Senate makes before the shutdown deadline. It is unclear whether Republicans who control the House can or would do so.
Some Democrats were already opposed to the funding measure, which, in addition to DHS, includes appropriations for the departments of Defense, Health and Human Services, Labor, Housing and Urban Development, Transportation, Education, State, and Treasury.
"No, I am not voting for this funding," said Minnesota Democratic Sen. Amy Klobuchar on NBC's "Meet the Press" on Sunday. "Our Republican colleagues have to stand up and stop this."
The top Democrat on the Senate Appropriations Committee, Sen. Patty Murray of Washington, has also said she will oppose the package if it includes DHS funding.
Murray warned earlier last week that the "suggestion that a shutdown in this moment might curb the lawlessness of this administration is not rooted in reality."
"Federal agents cannot murder people in broad daylight and face zero consequences," Murray said on X Saturday.
"I will NOT support the DHS bill as it stands. The DHS bill needs to be split off from the larger funding package before the Senate — Republicans must work with us to do that," she said.
It was unclear if the Senate could split the DHS portion off from the rest of the funding bill to minimize a partial shutdown.
While the House passed the DHS bill separately from the rest of the bills, they were all tied together into one bill to be sent to the Senate, meaning the majority of Republicans would need to support splitting the bill up.
It remains possible that enough Democrats join with Republicans to pass the funding bill and avoid a shutdown. Many of the other agencies in the package are important to Democrats.
DHS may also be less hindered during a shutdown if it taps the hundreds of billions of dollars that congressional Republicans injected into the agency as part of their "big beautiful bill" law passed last summer.
But that is far from a guaranteed outcome. Several Democrats who joined with Republicans last year to end the record 43-day government shutdown have warned they will oppose the bill if it includes funding for DHS.
"I will not support the current Homeland Security funding bill," said Sen. Catherine Cortez Masto, D-Nev., who is one of the Democrats who joined Republicans to end the last shutdown.
"Let's pass the remaining five bipartisan bills and fund essential agencies while we continue to fight for a Department of Homeland Security that respects Americans' constitutional rights and preserves federal law enforcement's essential role to keep us safe."Â Â
Complicating matters further is a massive snowstorm over Washington, D.C., and wide stretches of the U.S. The Senate canceled votes on Monday due to the storm, shortening an already tight timeline to avoid a shutdown.
— CNBC's Emily Wilkins contributed to this article.