VIENNA (AP) -- Diplomats say Iran and six world powers have reached tentative agreement on sanctions relief for Tehran as part of a nuclear deal.

Two diplomats tell The Associated Press that senior officials from Iran and the six nations it's negotiating with still have to sign off on the document outlining what sanctions will be lifted and when.

But the diplomats said on Saturday the document has been agreed on by experts for both sides who have been working on details of the outline to implement the preliminary agreement reached in November 2013.

Officials had described sanctions relief as one of the thorniest disagreements between Iran and the United States.

The diplomats demanded anonymity because they're not authorized to discuss the confidential negotiations.

By The Associated Press