Easing of Iran sanctions could start in December

The talks were also the culmination of a painstaking process of old-school contacts and secret sessions between Iranian and American envoys that began even before the surprise election of Iran's moderate-leaning President Hassan Rouhani last June.

The shadow dialogue, mediated by mutual ally Oman, was so sensitive that it was kept from even close allies, such as negotiating partners at the nuclear talks, until two months ago, according to details obtained by The Associated Press and later confirmed by senior administration officials.

The pace of the back-channel contacts picked up after Rouhani officially took office in August, promising a “new era” in relations with the West.