A senior Iranian official says nuclear talks between world powers and Tehran over Iran's atomic program have begun in the Iraqi capital.

Negotiators from the U.S. and five other world powers sat down Wednesday with a team of Iranian diplomats to try to hammer out specific goals in the yearslong impasse over Tehran's nuclear program.

Iran is demanding that the West outline timetables and steps ahead in gradually addressing international concerns over the Islamic Republic's nuclear ambitions.

The U.S. has been vague about its immediate goals.

Few believe the discussions in Baghdad will yield breakthroughs in the showdowns over Iran's nuclear program.