MADRID, Spain (AP) – Seeking to evade new U.N. sanctions, Iran has pledged to end years of stonewalling and provide answers on past suspicious activities to the U.N. nuclear monitoring agency probing its atomic program, an official said Friday.

The offer, which the official said was made Thursday by top Iranian nuclear negotiator Ali Larijani to EU foreign policy chief Javier Solana, falls short of the concession sought by the international community – a promise to freeze Iran’s uranium enrichment activities.

Iran refuses to consider such a freeze but the U.N. Security Council insists on it, and past meetings between Messrs. Solana and Larijani have made little progress on resolving the deadlock.

Mr. Larijani’s overture and the decision by Mr. Solana to treat the Iranian offer seriously, thus reflected mutual recognition that the talks needed to advance on other issues or face the risk of collapse.

Still, U.N. and other officials, who demanded anonymity because they were not authorized to discuss the issue, said any decision by Iran to fully cooperate on clearing up past activities would represent a major concession.

They told The Associated Press that such a move could help the International Atomic Energy Agency – the U.N. nuclear monitor – wrap up years of efforts to establish whether Tehran’s past nuclear strivings were exclusively peaceful in nature.

“This is the first time they made such a serious offer” without preconditions, said one of the officials, adding, without elaboration that Larijani had offered “a short timetable” for providing the answers sought by the IAEA.

The officials agreed that the move appeared to be an attempt by Iran to at least delay if not avoid the threat of new U.N. sanctions. An IAEA report last week provided the potential trigger for such penalties by saying Tehran continued to defy the Security Council ban on enrichment and instead was expanding its activities.

Mr. Larijani’s offer appeared designed to address another main concern in that report – refusal by Iran to provide answers on questionable activities during nearly two decades of clandestine nuclear activities that first came to light four years ago.

They include: traces of enriched uranium at a facility linked to the military – which could be a signs of a weapons program; lack of documentation on Iran’s past enrichment activities, and possession of documents showing how to form uranium metal into the form of missile warheads.