A partial shutdown of the US Government has begun after an eleventh-hour effort to secure a funding deal failed, in a chaotic close to Donald Trump's first year as President.

Key points: A stop-gap measure to stave off the shutdown for four weeks was defeated 50 votes to 48

A stop-gap measure to stave off the shutdown for four weeks was defeated 50 votes to 48 Trump has blamed the shutdown on the behaviour of the Democrats

Trump has blamed the shutdown on the behaviour of the Democrats The vast majority of Democratic senators won't support funding bill unless it includes protections for Dreamers

A stop-gap measure to stave off the shutdown for four weeks was approved by the Republican-controlled House of Representatives yesterday, but was blocked in the Senate in a dramatic late-night vote.

The White House blamed the shutdown on the Democrats, calling them "obstructionist losers, not legislators".

"Democrats are far more concerned with illegal immigrants than they are with our great military or safety at our dangerous southern border," Mr Trump tweeted after the shutdown began.

"They could have easily made a deal but decided to play shutdown politics instead."

The failure to secure a deal means the Government has technically run out of money, ensuring the closure of all but essential operations nationwide.

US troops will stay at their posts and mail will get delivered, but almost half of the 2 million civilian workers will be barred from doing their jobs if the shutdown extends into Monday.

It is the first time a shutdown has occurred while one party, in this case the Republicans, controls both Congress and the White House.

The vote on the stopgap plan was scheduled by the Senate after hours of heated closed-door meetings and phone calls, including with the White House.

The measure was defeated 50 votes to 48, short of the 60 votes needed to pass.

Democrats largely held together to block the legislation, digging in on their insistence that the spending bill include protections for some 700,000 younger immigrants facing deportation.

Known as "Dreamers", their right to remain in the US is due to be revoked in early March.

After the shutdown began, the White House said it would not negotiate the status of the Dreamers "while Democrats hold our lawful citizens hostage over their reckless demands".

"When Democrats start paying our armed forces and first responders we will reopen negotiations," it said in a statement.

'Blame falls on Trump's shoulders': Schumer

Senate Democratic leader Chuck Schumer said blame for the shutdown should "fall entirely on Mr Trump's shoulders".

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Mr Schumer said he had offered to put the border wall on the table during negotiations but that was not enough for the President to make a deal.

"When [Mr] Trump decides he is ready to lead his party to a deal, Democrats will be ready, willing and eager to clinch it," Mr Schumer said.

Vice-President Mike Pence weighed in on the standoff saying the actions of the Democrats were "unconscionable".

"As of tonight, due to a completely avoidable Government shutdown, [men and women in uniform] will stand their post without pay," he said.

Senate majority leader Mitch McConnell said he will seek a vote on a new bill to extend Government funding through February 8.

The shutdown, which has only happened three times in a meaningful way since 1995, will see hundreds of thousands of "non-essential" federal workers be told to stay home.

"Essential" employees, dealing with public safety and national security, will keep working.

Congress has been struggling for months to agree on long-term government funding levels but has been side-tracked by the dispute on immigration.

The Government has been operating on a third temporary funding measure since the new fiscal year began in October.

ABC/wires