Stock index futures dropped on Monday as a political impasse in Washington's debt ceiling talks fueled worries of a U.S. default, knocking world equities lower and pushing gold to a record high.

At 0813 GMT, futures for the S&P 500 were down 0.81 percent, Dow Jones futures down 0.79 percent and Nasdaq 100 futures down 0.59 percent.

Tokyo's Nikkei average <.N225> fell 0.8 percent, while European shares lost ground in early trade, halting a one-week rally, driven lower by banking stocks such as Barclays , BNP Paribas and UniCredit , down 2.4-2.7 percent. <.EU>

A divided U.S. Congress pursued rival budget plans on Sunday that appeared unlikely to win broad support, pushing the country closer to a debt default.

Analysts still expect a last-minute deal to raise the U.S. debt ceiling and avoid a default next week. But the impasse pushes the United States a step closer to losing its coveted triple-A credit rating as it seems unlikely that Democrats and Republicans will agree before the next election in November 2012 on how to find $4 trillion through government spending cuts and revenue increases.

White House Chief of Staff Bill Daley warned over the weekend there would be a few stressful days ahead for financial markets, with the deadline to lift the $14.3 trillion U.S. borrowing limit only nine days away.

DEBT DEAL

However, Treasury Secretary Timothy Geithner said on Sunday it was unthinkable for the United States not to meet its debt obligations and was confident a debt deal would be reached.

Concerns that a deal would not be forthcoming have weighed on equity markets, though some positive earnings news helped offset the issue. Major indexes notched solid gains last week, with the S&P and Nasdaq rising more than 2 percent.

The longer we go without a deal, the more you're going to see concerns on the negative side, said Alan Lancz, president of Alan B. Lancz & Associates Inc, an investment advisory firm based in Toledo, Ohio.

I don't think the initial reaction was overdone at all. This has to get behind us before the market can trend higher.

Also rattling investors on Monday, credit ratings agency Moody's cut Greece's sovereign debt by three notches on Monday to 'Ca', just one notch above default. The agency said the new bailout package set a negative precedent for creditors of other debt-burdened countries. The downgrade means Greece now has the lowest rating of any country in the world covered by Moody's.

Investors awaited earnings from a raft of companies on Monday, including Texas Instruments , Radioshack Corp , Kimberly-Clark , Broadcom and Anadarko Petroleum .

On Friday, promising chipmaker earnings and optimism that a solution was on the horizon for the U.S. debt stalemate triggered a move into growth-oriented shares such as techs.

The Dow Jones industrial average <.DJI> dipped 43.25 points, or 0.34 percent, to 12,681.16. The Standard & Poor's 500 Index <.SPX> added 1.22 points, or 0.09 percent, to 1,345.02. The Nasdaq Composite Index <.IXIC> gained 24.40 points, or 0.86 percent, to 2,858.83.

(Editing by Jane Merriman)