A Senate Banking Committee aide says the Democratic-led panel is gathering information on Standard & Poor's decision to issue the first-ever downgrade of the government's credit rating.

The aide spoke on condition of anonymity to discuss unannounced committee business after the panel's chairman, South Dakota Democratic Sen. Tim Johnson, called S&P's move "irresponsible." The aide did not say that a formal investigation was under way.

The credit rating agency announced Friday that it was reducing the government's credit rating from AAA to AA+, citing a partisan standoff in Washington over reducing the massive federal debt.

Administration officials have faulted S&P for using inaccurate numbers in making its decision. Democrats and Republicans have accused each other of refusing to budge in negotiations over how to reduce the red ink.