President Barack Obama called on Congress to act in the wake of the Standard & Poor's historic downgrade of the U.S. debt but defied the credit rating agency's conclusions. "Our problem is not a lack of confidence in our credit. Our challenge is the need to address our deficits over the longer term," Obama said. "But there's not much further we can cut in the long term." Banking analysts and famed investor Warren Buffett continued to downplay the downgrade and affirmed their bets on the bulletproof U.S. debt. However, markets continued the sell-off. Dow Jones Industrial Average losses passed more than 400 points as the president gave his first speech Monday after the S&P downgrade. "That threat has now roiled the market and slowed the pace of recovery," Obama said. The president then returned to a rhetoric displayed during the debt ceiling negotiations, calling on the new special committee to combine cuts in domestic and military spending with new tax revenue from the wealthy and reform of the overall tax code. S&P downgraded the triple-A status of the U.S. debt Friday for the first time since assigning it in 1941. Moody's Investors Service first assigned the gilt-edged rating in 1917. Moody's and Fitch Ratings both reaffirmed their triple-A ratings Monday. The debt ceiling negotiations ended in a compromised plan that would raise the cap on borrowing and cut an initial $917 billion in spending. But the contentious compromise left tougher political decisions on future cuts and possible new revenues to a super committee report due around Christmas. A minimum of $2.1 trillion in cuts is expected, but even if that is made, S&P said the new double-A-plus rating would only be confirmed. Obama pointed out initial proposals from both Republicans, Democrats and his early talks with Rep. John Boehner (R-Ohio) yielded plans to avoid a downgrade. Still, Obama said he would issue recommendations to the super committee over the coming weeks and called on Congress to extend payroll tax cuts and unemployment insurance immediately. "Markets will rise and fall, but this is the United States of America. No matter what some rating agency will say, we will always be and always have been a triple-A country," Obama said. Write to Jon Prior. Follow him on Twitter @JonAPrior.