A vote on the Republican bill to raise the US debt ceiling and prevent a default was delayed on Thursday.
House speaker John Boehner and Republican leaders have struggled to convince the majority of conservative Republicans.
Congress must raise the US debt limit by next Tuesday when the US Treasury has warned that the government will run out of money to pay its bills unless the £8.7trn borrowing limit is increased.
The Republicans hold 240 of the 433 votes to be cast in the House, and need 216 of their members to back the bill to pass it.
Meanwhile, the International Monetary Fund managing director Christine Lagarde has warned that the dollar’s standing as the world’s main reserve currency may be diminished if leaders fail to raise the debt limit.
She said: The US has an exorbitant privilege because it was the reserve currency that most central banks had. If there was a dent in this exorbitant privilege and the confidence that most people have in the dollar, it would probably entail a decline of the dollar relative to other countries.”