US Senators have for a fourth time failed to pass spending proposals to reopen the federal government, extending the ongoing shutdown into next week.

Two separate spending proposals - one from the Democrats and one from Republicans - failed to reach the required 60-vote threshold.

With both sides deadlocked, the White House on Friday said it would be left with the unenviable task of mass lay-offs to keep essential government services operating if the shutdown continues, which Press Secretary Karoline Leavitt described as fiscal sanity.

The scope of those potential lay-offs remain unclear but the White House has been in discussions with the Office of Management and Budget, or OMB.

Both Republican and Democratic lawmakers have dug in their heels on the main point of disagreement: healthcare. Democrats have hoped to capitalise on the impasse to ensure health insurance subsidies for those with low-income do not expire and reverse the Trump administration's cuts to the Medicaid health programme.

Republicans, for their part, have repeatedly accused Democrats of shutting down the government in a bid to provide healthcare to undocumented immigrants - a charge that Democratic leaders have denied.

A total of 54 Senators voted in favour of a Republican-led proposal to fund the government, with 44 against and two not voting.

A separate, Democrat-led proposal also failed, with 45 voting in favour and 52 against.

Both sides have continued to blame the other for the shutdown, with little sign of any progress in negotiations.

During a news briefing at the White House, Press Secretary Karoline Leavitt accused Democrats of holding Americans hostage over their demands.

As part of the federal government's response to the shut down, Vought on Friday announced the suspension of $2.1bn in federal infrastructure funding for Chicago, in addition to the previous freezing of $18bn in infrastructure spending in New York City and the cancellation of approximately $8bn in funding for federal energy projects in some Democratic-run states.