PRESS ASSOCIATION -- US Treasury secretary Timothy Geithner has said that credit rating agency Standard & Poor's showed "terrible judgment" in lowering the US government's AAA status.
Mr Geithner said the agency's decision showed a "stunning lack of knowledge" about the basic maths used to develop the government's budget.
Republicans have blamed President Barack Obama for the first downgrade of the government's credit rating, but Mr Geithner said Congress owned the credit rating because the US constitution gave Congress the power to tax and spend.
Standard & Poor's cut the nation's top-ranked AAA credit rating to AA+ on Saturday.
Finance ministers from major industrial countries have pledged increased co-operation to attack economic problems. The Group of Seven nations issued a joint statement saying they were committed to taking all necessary measures to support financial stability and growth.
The G7 statement came after the group held an emergency conference call to discuss the debt crisis in Europe and market prospects following the US downgrade.