The U.N. nuclear agency chief says Iran has provided a "substantive volume" of information for the agency's investigation of allegations that Tehran worked on nuclear arms.

But Yukiya Amano of the International Atomic Energy Agency is refusing to characterize the value of the documents.

Amano said Tuesday that would be premature. He told reporters that the IAEA needs "to see the whole picture to have an assessment."

Amano spoke on the sidelines of a meeting of the IAEA's 35-nation board convened to seek approval — and funds — for the agency's assigned task of monitoring the July 14 Iran nuclear deal.

That deal between Iran and six world powers seeks to crimp Iran's nuclear programs that could be used to make weapons and is formally separate from the probe.