The White House has urged Congress to "do its job" and find a solution to end a fiscal impasse over raising the US debt ceiling after the Senate rejected a Democratic plan.
A statement from White House press secretary Jay Carney said it was unfortunate that the Senate Democratic plan failed to pass because it would have taken the threat of a debt default off the table ahead of a looming Thursday deadline.
Carney said: "Congress must do its job and raise the debt limit to pay the bills we have incurred and avoid default.
"Congress needs to move forward with a solution that reopens the government and allows us to pay our bills."
The US shutdown is but a precursor to a much bigger problem - in a couple of weeks the government, shutdown or not, will run out of cash.
Landmarks across the US have closed as the Congress failed to reach a deal over the budget.