AP sources: Searching for a diplomatic formula with Iran, US weighs an expanded offer

Officials say the U.S. is considering a new approach in negotiations to curb Iran's nuclear program that would ease economic sanctions faster than previously offered if Tehran makes greater concessions than it has ever discussed.

The proposal is among several being discussed amid an upsurge in diplomatic activity since President Barack Obama won re-election, and as world leaders prepare for future talks with Iran.

The U.N.'s International Atomic Energy Agency announced Friday talks of its own in Tehran in December.

Meanwhile, a Western official says negotiators from the U.S., Britain, China, France, Germany and Russia will meet Nov. 21 in Brussels, in a prelude to a possible resumption of talks with Iran early next year.

Officials spoke on condition of anonymity because they weren't authorized to discuss the issue publicly.