Stocks later trimmed their gains after President Barack Obama said any deal with Congress to avert a fiscal crisis must come with higher taxes on the wealthiest Americans.

US Treasury bonds cut losses to trade almost flat on Obama's remarks, in which the newly re-elected president invited congressional leaders to the White House next week to start negotiating.

A 3.5 percent gain in gold prices this week was bullion's biggest weekly rise since late August and reflected a hedge against economic uncertainty.

The so-called fiscal cliff, aimed at cutting the federal budget deficit, could take an estimated $600 billion out of the economy in automatic spending cuts and tax hikes, severely hindering economic growth.

"Clearly taxes are going up and that is something the market doesn't like. There is concern the economy continues to weaken, and there is not much left in the tank in terms of making corporate profitability better," said Stephen Massocca, managing director at Wedbush Morgan in San Francisco.

The surprisingly strong sentiment survey showed American consumers felt more optimistic about employment prospects and the economic outlook, according to a Thomson Reuters/University of Michigan index, easing the gloom from Europe.

MSCI's world equity index slipped almost 2.2 percent this week, the steepest weekly decline since the start of June. The index fell 0.1 percent to 323.27.