Diplomats said on Thursday that Iran has agreed to discuss charges that it secretly worked on nuclear arms, after refusing to do so for years.

Two diplomats told the Associated Press that the topic will be a main focus of talks set for January 28, during a visit to Tehran by senior officials of the International Atomic Energy Agency.

No date has previously been mentioned for the trip. Thursday's comments by the diplomats were also the first word that Iran was ready talk about the allegations after stonewalling requests to do so for more than three years. The diplomats spoke condition of anonymity because of confidentiality rules.

Faced with Iranian stonewalling, the IAEA summarized its body of information in November, in a 13-page document drawing on 1,000 pages of intelligence. It stated then for the first time that some of the alleged experiments can have no other purpose than developing nuclear weapons.

Iran continues to deny the charges and no change in its position is expected during the Tehran talks with IAEA officials. But even a decision to enter a discussion over the allegations would be a major departure from outright refusal to talk about them - and create hopes of future progress in the investigation.

Ali Asghar Soltanieh, Iran's chief IAEA delegate, declined to be drawn on what would be discussed in Tehran, indicating in comments to The AP that it was too early to go public with details.