The federal government entered a partial shutdown at midnight EST after the House and Senate adjourned without a spending deal on Friday night.

The shutdown is the result of a last-minute flip-flop by President Donald Trump on his demands for money for a US-Mexico border wall.

Trump's demands led to gridlock in Congress on a broader funding bill.

The shutdown will force 800,000 federal workers to go without pay for as long as the government remains closed.

In a joint statement issued after the shutdown officially took effect, the Democratic Speaker-designate Nancy Pelosi and Senate Democratic leader Chuck Schumer said, "President Trump has said more than 25 times that he wanted a shutdown and now he has gotten what he wanted."

The federal government entered a partial shutdown as the House and Senate adjourned without a federal-spending deal on Friday, hours before a midnight EST deadline.

President Donald Trump's demands for a wall along the US-Mexico border led to a standoff in the Senate.

Trump's sudden turnaround after supporting a short-term funding extension left Congress with little time to find a compromise that would prevent a shutdown.

Without a deal, a substantial portion of the federal government closed at midnight, and it is unclear when the two parties will be able to find an agreement to reopen those departments.

In a joint statement issued after the shutdown officially took effect, the Democratic Speaker-designate Nancy Pelosi and Senate Democratic leader Chuck Schumer said, "President Trump has said more than 25 times that he wanted a shutdown and now he has gotten what he wanted."

House Minority Leader Nancy Pelosi and Senate Minority Leader Chuck Schumer got into a heated debate with Trump about the funding earlier this month. Associated Press/Evan Vucci

"Democrats have offered Republicans multiple proposals to keep the government open, including one that already passed the Senate unanimously, and all of which include funding for strong, sensible, and effective border security – not the president's ineffective and expensive wall," the joint statement reads.

"If President Trump and Republicans choose to continue this Trump Shutdown, the new House Democratic majority will swiftly pass legislation to re-open government in January."

How did we get here?

The shutdown is the culmination of weeks of debate between Democrats and Trump over the border-wall funding. Here's how it broke down:

December 6: Congress passes a short-term funding bill to delay the shutdown until after the date of President George H.W. Bush's funeral.

Congress passes a short-term funding bill to delay the shutdown until after the date of President George H.W. Bush's funeral. December 11: Democratic leaders and President Donald Trump meet to discuss the funding deadline. Trump demands $5 billion in border-wall funding, Democrats counter with an offer of $1.6 billion in general border-security funding. Trump rejects the idea and offers to take the blame for the shutdown. The president says he would be "proud" to shut down the government.

Read more: Trump says 'Democrats now own the shutdown' just 10 days after declaring he was 'proud to shut down the government'

December 19: The Senate passes a clean short-term funding bill, called a continuing resolution (CR), that does not include border-wall funding but will keep the government open until February 8. Trump supported the bill at the time, Senate GOP leaders said.

The Senate passes a clean short-term funding bill, called a continuing resolution (CR), that does not include border-wall funding but will keep the government open until February 8. Trump supported the bill at the time, Senate GOP leaders said. December 20: Trump flip-flops on the clean CR after listening to attacks from conservative TV pundits and the hardline House Freedom Caucus, and he announces that he will not sign a bill with no wall funding. House Republicans then pass a CR that includes $5.7 billion in wall funds.

Trump flip-flops on the clean CR after listening to attacks from conservative TV pundits and the hardline House Freedom Caucus, and he announces that he will not sign a bill with no wall funding. House Republicans then pass a CR that includes $5.7 billion in wall funds. December 21: Trump demands the Senate vote for the House version of the CR and tells Senate Majority Leader Mitch McConnell to get rid of the legislative filibuster in order to pass the vote with only GOP lawmakers, but the idea is a nonstarter. The Senate votes down the House version of the bill, and the government moves closer to a shutdown at the midnight deadline.

What does the shutdown mean?

The shutdown does not affect the entire federal government since Congress already passed seven of the 12 major funding bills for next year. But the shutdown does impact a slew of agencies, including the departments of Agriculture, Commerce, Justice, Homeland Security, the Interior, State, Transportation, and Housing and Urban Development.

About 800,000 federal workers from those agencies will be affected by the shutdown. Some 420,000 workers will be forced to work without pay since they are considered "essential" employees. The other 380,000 workers will be furloughed, which means they will be barred from work and will not receive pay.

Everglades National Park during the 2013 shutdown. Joe Raedle/Getty Images

According to the Committee for a Responsible Federal Budget (CRFB), the shutdown will result in the closure of a number of nonessential services in those impacted departments.

"Functions that would be stopped during a shutdown include entry into national parks, Environmental Protection Agency (EPA) site inspections, refunds and audits by the Internal Revenue Service, several Federal Aviation Administration activities outside of air traffic control services, and vehicle safety activities and research," the CRFB said.

The workers could receive back pay, but Congress would first need to pass a bill giving those employees the money. Members of Congress still receive paychecks during a shutdown.

Is there a way forward?

It's unclear if there is a deal on the table that would pass both chambers of Congress and get Trump's signature, and many lawmakers are anticipating a long-term shutdown, if those circumstances materialize.

The president even told reporters on Friday that a government shutdown may last for an extended period of time.

"I hope we don't, but we are totally prepared for a very long shutdown," Trump said during a meeting in the Oval Office.