Iran has agreed to open its nuclear activities to greater purview for UN experts seeking to revive their probe into suspicions that Tehran might have worked on atomic weapons.

Substantial progress in restarting that probe after more than six years of inconclusive attempts would be a breakthrough for the UN’s International Atomic Energy Agency (IAEA).

But both Iran and the IAEA spoke of progress in a process that the agency hopes will unroll as a step-by-step approach to unresolved questions, starting with less sensitive issues and progressing to the arms-related queries.

Mideast Iran Military Parade

The two sides reached an agreement three months ago.

The process began after the two sides reached an agreement three months ago that gave the agency access to several previously off-limit sites not directly linked to any suspected weapons activities.

An IAEA statement said Iran had complied with the first steps of that deal and both sides on the weekend signed off on an additional “seven practical measures” to be implemented by Iran by May 15.

The Islamic Republic’s official IRNA news agency said Iran will provide information on mines, facilities and source materials of nuclear and laser activities.

“These are small steps, but information on source material is important, if it is provided in a verifiable manner,” said Olli Heinonen, who formerly led the agency’s Iran probe.