U.S. sanctions threat hangs over Iran talks in Geneva

WASHINGTON (Reuters) - A threat by the U.S. Congress to slap tough new sanctions on Iran hung over negotiations on Tehran's nuclear program on Thursday, even as diplomats at talks in Geneva voiced optimism an agreement was close.

A package of tighter sanctions on Iran has been making its way through Congress but was held up after President Barack Obama's administration asked for a delay to let the delicate diplomatic talks over Tehran's nuclear program unfold.