The US government officially shut down on Saturday, the first anniversary of President Donald Trump's inauguration, after lawmakers failed to agree a stop-gap spending deal.
Senators were still negotiating on the Senate floor as the clock turned midnight, but Trump's office issued a statement blaming opposition Democrats for the crisis.
In the late-night vote, Senate Democrats joined to block a bill that would have kept the government running for another four weeks. A flurry of last-minute negotiations failed to beat the deadline.
Democrats have tried to use the Friday night funding deadline to win concessions from Republicans, including an extension of an Obama-era program protecting some young immigrants from deportation. The program is set to expire in March. Republicans sought more time for talks, but Democrats refused.
The shutdown is only the fourth government closure in a quarter-century. It will only partially curb government operations.
Uniformed service members, health inspectors, and law enforcement officers are set to work without pay.
Many of the immediate effects of the government shutdown will be muted for most Americans, as it comes on a Friday night.
Social Security and most other safety net programs are unaffected by the lapse in federal spending authority. Critical government functions will continue, with uniformed service members, health inspectors and law enforcement officers set to work without pay.
But if no deal is brokered before Monday, hundreds of thousands of federal employees are set to be furloughed.
The White House and Capitol Hill will be working with skeleton staffs, but some government agencies, like the Environmental Protection Agency, have said they were able to shift funding around to keep most workers on the job. National parks and federal museums will be open, but with potentially reduced services.