U.S. - door still open on Iran atom talks, but not forever

ISTANBUL (Reuters) - U.S. Secretary of State John Kerry said on Sunday world powers would pursue further talks with Iran to resolve a decade-old dispute over its nuclear programme, but stressed that the process could not go on forever.

The six powers and Iran failed again to bridge wide differences at weekend talks in Kazakhstan, prolonging a stand-off that could yet erupt into a new Middle East war. No new talks were scheduled.