Troops and Defense Department civilians faced the possibility of frozen pay and furloughs as the government shut down on Saturday after last-minute efforts on Capitol Hill to pass protections fizzled.

Sen. Claire McCaskill, D-Mo., proposed fast-tracking a bill on the Senate floor after a midnight budget deadline Friday that would have ensured paychecks continued. But the move was opposed by Majority Leader Mitch McConnell, R-Ky., leaving the military and hundreds of thousands of civilian workers hanging.

“I want to send a very clear signal that we don’t want any moment to pass with there being any uncertainty with any soldier anywhere in the world that they will be paid for the valiant work that they do on behalf of our national security,” McCaskill said.

During the last government shutdown in 2013, Congress passed legislation in advance that kept troops paid and allowed about 350,000 furloughed Defense Department civilians to return to work. This time, bills were filed in both the House and Senate in the hours before the deadline and went nowhere.

The next military pay date is Feb. 1, and many workers are likely off for the weekend, so there may be no immediate threat to military checkbooks, but Defense Secretary Jim Mattis noted the potential hardship in a memo sent out Friday when the shutdown became certain.

“I recognize the consequences of a government shutdown,” Mattis wrote. “You have my personal commitment that the department’s leadership will do our best to mitigate the impacts of the disruptions and any financial burdens to you and your families.”

Active-duty troops are required to show up to work during a shutdown but will not get paid on schedule until a new federal budget is passed. War operations in Iraq, Syria, and Afghanistan will also continue.

The Defense Department’s 750,000 or so civilian workers potentially face more financial hardship. They will be sent home without pay if they are not deemed crucial to safety and protection of the military. Congress would likely need to pass legislation for furloughed workers to go back to work or receive back pay after the shutdown.

Meanwhile, President Trump, Democrats, and Republicans traded recriminations over who caused the government shutdown and a solution remained uncertain by midday Saturday.

“Democrats are holding our Military hostage over their desire to have unchecked illegal immigration. Can’t let that happen!” Trump tweeted.

McConnell said the public will blame Democrats for the shutdown, which became inevitable after negotiations over immigration reform and lifting federal spending caps for 2018 fell apart.

Senate Democrats under Minority Leader Chuck Schumer, D-N.Y., locked arms against a Republican stopgap budget measure that would have kept the government open through Feb. 16 and renewed the Children’s Health Insurance Program because it did not include protections for about 700,000 illegal immigrants brought into the country as children.

Americans “cannot comprehend why the senior senator from New York is advising his party to keep the government shuttered for American troops, American veterans, American military families, and vulnerable American children until he gets exactly what he wants on the issue of illegal immigration – a situation which does not even become urgent until March,” McConnell said on the Senate floor Saturday.

Schumer, in a press conference Saturday, blamed a lack of communication and coordination among the GOP and the White House for scuttling negotiations on a budget deal.

“Republicans in Congress plunged head-first into the Trump shutdown,” Schumer said. “Over the last several months Democrats have bent over backwards to negotiation with the White House.”