The official also warned that if Iran does not live up to its commitments, relief would be terminated, and the world powers would ratchet up the pressure even further by adding new sanctions.
Delegates of the six world powers, known as the P5Ư group, started another round of nuclear talks with Iran in Geneva, Switzerland, Thursday.
In the two-day talks, the world powers are expected to seek a " first step" deal with Iran on solving the nuclear problem, though both sides say an agreement is far from certain.
In the previous round of talks, held Oct 15-16, Iran proposed a plan as a basis for negotiation but details of the proposal were not disclosed.
