BEIRUT, Lebanon — International arms inspectors brokered an agreement with Tehran to discuss alleged evidence of nuclear weapons experiments, officials said yesterday, signaling a potential breakthrough in negotiations over Iran’s controversial research program.

Arms control experts called the evidence “the alleged studies of weaponization.” The material was discovered on a laptop computer purportedly smuggled out of Iran and given to American officials. Its authenticity has long been a bone of contention between Tehran and international inspectors.

Insisting its nuclear program was peaceful, Iran previously has refused to discuss the evidence. The secretary-general of the International Atomic Energy Agency, Mohamed ElBaradei, told reporters the agreement to talk was a “certain milestone,” news agencies reported.

But other arms control experts cautioned that merely addressing the evidence on the laptop did not amount to explaining away patterns of behavior and forensic evidence Western officials consider consistent with a clandestine nuclear arms program.

“These accusations have been around for some time,” said James Acton, a nuclear arms expert in the Department of War Studies at King’s College London.

“The fact that Iran is willing to discuss them doesn’t mean they’re going to discuss them constructively or usefully,” he said.

The alleged studies came to light in 2005 after American officials obtained a laptop computer that purportedly contained files with schematics for warhead designs, uranium enrichment experiments, and explosives testing consistent with a nuclear weapons program.