Negotiations over Iran's nuclear program are entering their 17th — and possibly last — day in Vienna as diplomats continue to haggle over details ahead of the expiration of an interim accord.

With the temporary deal set to expire at midnight Monday, diplomats said they were planning to complete and announce a final agreement before day's end. But, they warned there was no guarantee.

The deadline for the end of the current round of negotiations has already been extended three times and diplomats said there was little appetite for a fourth.