The head of the U.N. nuclear agency is indicating that his attempted probe of allegations that Iran worked on nuclear arms is going slowly.

Yukiya Amano of the International Atomic Energy Agency says that Tehran has not met his request to propose two new areas of investigation by Sept. 2.

He says that discussions have begun on two other alleged series of experiments that the two sides agreed on earlier but does not say whether his agency is getting the answers it seeks.

Amano spoke Monday to the opening session of the IAEA's 35-nation board meeting.

Iran says it does not want nuclear arms and never worked toward them. But the agency says it has collected about 1,000 pages of information that point to attempts to develop such weapons.