US President Donald Trump has warned of “a very long” government shutdown if the Senate does not approve his demand for $5 billion toward funding his long-promised border wall.

Trump made the remarks on Friday after a meeting with Senate Republicans at the White House, which he described as "great."

"Now it's up to the Democrats as to whether or not we have a shutdown tonight," he said, adding, "I hope we don't."

However, he said, "we are totally prepared for a very long shutdown and this is our only chance that we’ll ever have in our opinion, because of the world and the way it breaks out, to get great border security."

Earlier on the day, Trump took to Twitter, trying to put the blame on Democrats for having a possible shutdown.

The Democrats, whose votes we need in the Senate, will probably vote against Border Security and the Wall even though they know it is DESPERATELY NEEDED. If the Dems vote no, there will be a shutdown that will last for a very long time. People don’t want Open Borders and Crime! — Donald J. Trump (@realDonaldTrump) December 21, 2018

His Friday’s warning came prior to a midnight deadline for him and Congress to reach an agreement on a spending bill to avert the shutdown, which would affect about 800,000 of the 2.1 million federal employees in the United States.

Some 380,000 federal workers would be forced to take a furlough, or be put on unpaid leave, including 52,000 employees of the Internal Revenue Service.

In addition, nearly 80 percent of the employees of the National Park Service, 96 percent of NASA workers as well as 86 percent of the Commerce Department would be sent home.

Another 420,000 workers regarded as essential personnel would have to work without pay including 41,000 federal law enforcement and correctional officers and others like aviation and postal workers.

On Thursday, Trump said he would not sign the congressional bill for government funding unless it includes a budget for the construction of the border wall.

Although his rejection of the bill sent lawmakers scrambling for a new compromise, Democrats have stood firm, saying they will not support a spending measure that funds the wall.