The US Secretary of State, John Kerry, yesterday warned that the partial shutdown of the country's government sends a message to the world that Americans "can't get our own act together", encouraging others to make "mischief".
Mr Kerry said security assistance to key allies such as Israel and sanctions against countries like Iran could be affected by what he described as a "moment of political silliness".
The shutdown of non-essential government operations began on Tuesday when the Republicans in the House of Representatives refused to pass next year's budget because the Democrats insisted they would not delay implementation of Obama's landmark 2010 healthcare law, known as "Obamacare". Thousands of staff have been sent home without pay.
Speaking on the sidelines of the Asia-Pacific Economic Co-operation forum in Bali yesterday, Mr Kerry cautioned any states thinking of trying to take advantage of the situation that "we will continue to fulfil our responsibilities and engagement around the world".
"There are momentary disruptions, and momentary disruptions always have the ability to have an impact. There is an opportunity for mischief," Mr Kerry said. "To all of our friends and foes around the world: do not mistake this... for anything less than a moment of politics or anything more than a moment of politics."
He added: "When we get this... political silliness behind us, we will get back on a track the world will respect and want to be part of." He urged US politicians to "end it now, end it today".
However, radio addresses by President Barack Obama and the Republicans yesterday suggested that the stalemate was set to continue for some time. Congress must act by 17 October to avoid defaulting on the government's debt, which some analysts believe could cause an economic depression.
Mr Obama said that he would not allow the Republicans to "hold our democracy and our economy hostage over a settled law". He said: "It's not how our democracy is supposed to work."
Texas Senator John Cornyn said in the Republicans' weekly address that the Democrats were trying to "bully" his party.