Iran's chief nuclear negotiator Saeed Jalili (3rd L) and his aides meet with representatives of six world powers for the second day of talks at the Ciragan Palace in Istanbul January 22, 2011. – Photo by Reuters

ISTANBUL: The inconclusive end to a two-day meeting between six world powers and Iran over its nuclear programme was “disappointing”, but there was no breakdown in the talks, a senior US official said on Saturday.

Talking to journalists after the talks ended without any concrete result, or even agreement to meet again, the official said “serious differences remained”.

During the talks, Iran had refused a request to hold a bilateral with the US delegation headed by Under-Secretary for Political Affairs Bill Burns.

Since the fall of the US-backed shah in Iran in 1979 direct contacts between the United States and the Islamic Republic have been rare and have usually taken place behind the scenes.