WASHINGTON — The killing of a second U.S. citizen by federal agents in Minneapolis is deeply complicating efforts to avert another government shutdown in Washington as Democrats — and some Republicans — view the episode as a tipping point in the debate over the Trump administration’s immigration enforcement policies.

Senate Democrats pledged to block funding for the Department of Homeland Security unless changes are made to rein in the federal agency’s operations following the killing of Alex Pretti, a 37-year-old intensive care unit nurse.

The Democratic defections threaten to derail passage of a broad spending package that also includes funding for the State Department and Pentagon, as well as education, health, labor and transportation agencies. Senate Democratic Leader Chuck Schumer (D-N.Y.) released a statement Monday calling on Republican Leader John Thune (R-S.D.) to avert another shutdown by separating funding for Homeland Security from the full appropriations package.

“Senate Democrats have made clear we are ready to quickly advance the five appropriations bills separately from the DHS funding bill before the January 30th deadline. The responsibility to prevent a partial government shutdown is on Leader Thune and Senate Republicans,” Schumer said.

The standoff also revealed fractures among GOP lawmakers, who called for a federal and state investigation into the shooting and congressional hearings for federal officials to explain their tactics — demands that have put unusual pressure on the Trump administration.

Senate Republicans must secure 60 votes to advance the spending measure in the chamber — a threshold they cannot reach on their own with their 53 seats. The job is further complicated by a time crunch: Lawmakers have until midnight Friday to reach a compromise or face a partial government shutdown.

Senate Democrats already expressed reservations about supporting the Homeland Security funding after Renee Good, a mother of three, was shot and killed this month by federal agents in Minneapolis. But Pretti’s killing led Democrats to be more forceful in their opposition.

Sen. Adam Schiff (D-Calif.) said Sunday he would oppose funding for Immigration and Customs Enforcement and Customs and Border Protection, the agencies involved in the Minneapolis operations.

“I’m not giving ICE or Border Patrol another dime given how these agencies are operating. Democrats are not going to fund that,” he said in an interview with NBC’s “Meet the Press.” “I think anyone who votes to give them more money to do this will share in the responsibility and see more Americans die in our cities as a result.”

Sen. Alex Padilla (D-Calif.) said in a statement last week that he would not “give more money to CBP and ICE to continue terrorizing our communities and breaking the law.” He reiterated his stance hours after Pretti’s killing.

“I will vote against any additional funding for Trump’s ICE and CBP while they act with such reckless disregard for life, safety and the Constitution,” Padilla wrote on social media.

While Senate Republicans largely intend to support the funding measure, some are publicly raising concerns about the Trump administration’s training requirements for ICE agents and calling for congressional oversight hearings.

“A comprehensive, independent investigation of the shooting must be conducted in order to rebuild trust and Congressional committees need to hold hearings and do their oversight work,” Sen. Lisa Murkowski (R-Alaska) wrote on social media. “ICE agents do not have carte blanche in carrying out their duties.”

Similar demands are being made by House Republicans.

Rep. Andrew Garbarino (R-N.Y.), the chairman of the House Homeland Security Committee, formally sought testimony from leaders at ICE, Customs and Border Protection and Citizenship and Immigration Services, saying his “top priority remains keeping Americans safe.”

Homeland Security has not yet provided a public confirmation that it will attend the hearing, though Garbarino told reporters Saturday he has been “in touch with the department” and anticipates a full investigation.

Many Republican lawmakers expressed concern over federal officials saying Pretti’s killing was in part because of him having a loaded firearm. Pretti had a permit to carry, according to the Minneapolis police chief, and videos show him holding a cellphone, not brandishing a gun, before officers pushed him to the ground.

“Carrying a firearm is not a death sentence, it’s a constitutionally protected God-given right, and if you don’t understand this you have no business in law enforcement of government,” Rep. Thomas Massie (R-Ky.) wrote on social media.

Following pushback from the GOP, President Trump appears to be seeking ways to tone down the tensions. The president said Monday he had a “very good call” with Minnesota Gov. Tim Walz, a Democrat he clashed with in recent weeks, and that they “seemed to be on a similar wavelength” on next steps.

If Democrats are successful in striking down the Homeland Security spending package, some hinted at comprehensive immigration reforms to follow.

California Rep. Ro Khanna (D-Fremont) detailed the plan on social media over the weekend, calling on Congress to repeal the $75 billion in supplemental funding for ICE in the One Big Beautiful Bill Act last year. The allocation roughly tripled the budget for immigration enforcement.

The shooting came as a slate of progressives renewed demands to “abolish ICE” and replace it with an agency that has congressional oversight.

Congress must “tear down and replace ICE with an agency that has oversight,” Khanna said. “We owe that to nurse Pretti and the hundreds of thousands on the streets risking their lives to stand up for our freedoms.”

Democrats also are focusing on removing Homeland Security Secretary Kristi Noem. This month Rep. Robin Kelly (D-Ill.) introduced a measure to impeach Noem, saying she has brought about a “reign of terror to Minneapolis.” At least 120 House Democrats have supported the measure, according to Kelly’s office.

Democrats also urged a stop to controversial “Kavanaugh stops,” which allow agents to detain people based on perceived race, and have set their sites on the reversal of qualified immunity protections, which shield agents from misconduct lawsuits.

Rep. Ilhan Omar (D-Minn.) backed the agenda and called for ICE and Border Patrol agents to “leave Minnesota immediately.”

“Voting NO on the DHS funding bill is the bare minimum. Backing Kristi Noem’s impeachment is the bare minimum. Holding law-breaking ICE agents legally accountable is the bare minimum. ICE is beyond reform. Abolish it,” she wrote Sunday on social media.