The US government shutdown has entered its sixth day, with President Donald Trump's Republicans and congressional Democrats still at an impasse and the White House threatening to ramp up pressure by ordering mass lay-offs of federal workers.

The Republican-led Senate on Monday was slated to vote again on duelling measures to fund federal agencies, including a Republican stopgap bill approved by the House of Representatives that would fund operations through November 21, and a Democratic alternative.

Neither was expected to receive the 60 votes needed to advance.

Asked on Sunday night when the government would begin laying off federal workers, Trump said: "It's taking place right now."

He blamed Democrats for the impasse but did not elaborate on the lay-off plans.

Trump's budget direct

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