Washington DC - President Joe Biden on Saturday blamed "a small group of extreme Republicans" for a budget impasse that has placed the US government a week away from a shutdown, urging the lawmakers to resolve the issue.

Speaking at a Congressional Black Caucus awards dinner, Biden said he and top House Republican Kevin McCarthy had previously agreed on government spending levels.

"Now a small group of extreme Republicans don't want to live up to the deal, so now everyone in America could be forced to pay the price," he said.

US lawmakers have until midnight on September 30 to reach an agreement on a spending bill, before funding for government services is due to dry up.

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"Funding the government is one of the most basic responsibilities of Congress. It's time for Republicans to start doing the job America elected them to do. Let's get this done," Biden added.

A government shutdown would put the finances of hundreds of thousands of workers at federal parks, museums, and other sites at risk, but it could also carry significant political costs for Biden, who is running for re-election.

The White House wants any budget bill passed by lawmakers to include $24 billion in military and humanitarian aid for Kyiv.

While the plan is supported by Democrats and Republicans in the Senate, it is radically opposed by some members of the House.

The standoff – encouraged by ex-President Donald Trump – has also left House Speaker McCarthy's already weak position in even more doubt.