The US Senate failed for a fifth time on Monday to pass spending measures that would reopen the government.

Competing proposals by Democrats and Republicans were both shot down, failing to meet the 60-vote threshold required.

Donald Trump had reiterated threats of mass layoffs if another vote failed earlier in the day. Thousands of federal employees were furloughed or ordered to work without pay when funding for their agencies ended five days ago.

But the US president hinted that he was open to trying to end the impasse and possibly strike a deal with Democrats who are sticking to demands that the legislation address healthcare. Republicans are pressing for a clean funding bill.

The Democratic-led bill to extend the government's funding failed first on Monday with a 45-50 vote. Its Republican counterpart then fell short at 52-42.

Soon after the vote, Trump took to social media to blame Democrats for shutting down the government.

Democrats have held out on supporting the Republican-led proposal because they say it undercuts medical access for lower-income Americans. They want any funding bill to ensure health insurance subsidies for lower-income Americans do not expire and to reverse the Trump administration's cuts to the Medicaid health programme.

Recent polling found that Americans view both parties' handling of the shutdown unfavourably, with Trump and congressional Republicans being blamed slightly more for the situation.