Washington DC - President Donald Trump's administration has used the government shutdown as an opportunity to fire more than 4,000 federal workers over the last two weeks.

A statement filed by the Department of Justice on Tuesday revised down the number of federal workers dismissed in the two weeks since the government shutdown began from 4,278 to 4,108, Reuters reported.

Trump blamed the cuts on the government shutdown and, by extension, on the Democrats for failing to capitulate in efforts to pass a stopgap spending bill.

Democrats have demanded a funding deal include extensions of expiring health care subsidies, without which millions of Americans could see their insurance premiums rise sharply, but Republicans have refused to bend.

The president has also put pressure on Democratic leadership by threatening to specifically target programs instituted and supported by the Democrats in future cuts.

More than two million people are employed by the US government, with Trump issuing threats of mass layoffs going into the shutdown.

Federal workers' unions are taking legal action against the Trump administration over the firings, arguing that layoffs are outlawed during a government shutdown because they are not an essential service.

Democratic Congressman from Virginia James Walkinshaw slammed the layoffs in a recent appearance on Fox News, and revealed that he is calling on the US Government Accountability Office to investigate.

"I think it's obviously an outrageous thing for the administration to inflict pain on the American people because of this Trump shutdown," Walkinshaw said.

"The law is very clear," he went on. "The Antideficiency Act lays out what the administration can and cannot do during a shutdown."

"One of the things that they cannot do is implement and execute this kind of large-scale layoff... It's flatly illegal."