The U.N. atomic agency's chief inspector said Friday he held "very constructive" talks with Iran over its nuclear program and announced a new meeting next month.

"We agreed to meet again on Oct. 28 when we will start substantial discussions on the way forward to resolving all outstanding issues," Herman Nackaerts of the International Atomic Energy Agency told reporters, calling Friday's talks "very constructive".

The IAEA wants Iran to grant it access to people, documents and sites related to Iran's alleged efforts, mostly before 2003, to develop nuclear weapons.

Ten previous meeting have failed but Friday's was the first since moderate Iranian President Hassan Rouhani was elected in June, who has been sounding more conciliatory than his predecessor.

This week in New York there were a flurry of meetings at the U.N. General Assembly including between Iran's foreign minister and his counterparts from six world powers including John Kerry of the United States.

These were focused more on Iran's current activities, most notably uranium enrichment. (AP)