VIENNA (AP) — The U.N. atomic agency reports progress in its long-stalled probe of allegations that Iran secretly tried to develop nuclear arms.

The agency says Tehran has agreed to “exchange information” on suspicions that it experimented with high explosives as part of a possible effort to set off a nuclear charge.

It also said Wednesday that Iran has agreed to provide further answers on allegations that it worked on models of a nuclear warhead.

The International Atomic Energy Agency announced the developments after a visit to Tehran Monday by an IAEA delegation.

Iran denies any interest — or work on — nuclear arms. But after years of deadlock, it promised to cooperate last year in hopes that will advance its goal of an end to all sanctions that are choking its economy.

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