The head of the UN nuclear watchdog has called on Iran to do more to co-operate with the agency's inspections.
Suspicions remain over Iran's nuclear ambitions despite extensive inspections
IAEA head Mohamed ElBaradei said that inspections were "moving forward", but the agency was still not sure it had seen all areas of Iran's activities.
The IAEA board is meeting to discuss Iran, North Korea, and who will become the body's next director general.
Correspondents say the IAEA is unlikely to criticise Iran for failing to reveal all aspects of its nuclear programme.
After two years, the International Atomic Energy Agency has failed to prove or disprove US claims that Iran is secretly trying to make nuclear arms.
Yet suspicions, particularly from Washington, remain high. The US accuses Iran of using its civilian nuclear power programme as a cover to develop nuclear bombs.
Tehran insists its nuclear programme is peaceful.
Late last year, Tehran agreed with the European Union to freeze its uranium enrichment programme - a process which can be used for nuclear power plants or nuclear weapons.
France, the UK and Germany are now trying to persuade Iran to make the freeze permanent in exchange for trade and technology benefits.
In the US, the Washington Post has reported that the US administration is close to a decision to join Europe in the offer of incentives to Iran - possibly including eventual membership in the World Trade Organization - in exchange for Tehran's formal agreement to give up any plans to develop a nuclear weapon.
As well as Iran, the IAEA's board is to discuss who will be the next director general of the agency.
Mr ElBaradei is standing for a third term in the post.
The US wants him to step down, accusing him of being too soft on Iran.
However, he has wide support among other board members.