The head of the International Atomic Energy Agency says Iran, North Korea and Syria are not cooperating fully with the IAEA on their nuclear pursuits.

In his annual report to the United Nations General Assembly, IAEA chief Yukiya Amano questioned their implementation of nuclear safeguards.

He said the IAEA cannot provide "credible assurance" regarding undeclared nuclear material and activities in Iran, and thus cannot say all nuclear material there is intended for peaceful purposes.

Iran says its atomic program has peaceful aims while many Western nations fear it is working towards developing nuclear weapons.

On North Korea, Amano said Pyongyang is in "clear violation" of U.N. Security Council resolutions.

He said he regrets North Korea's statements about a third nuclear test and its intention to restart its nuclear facilities at Yongbyon.

Amano also urged Syria to cooperate with the IAEA on unresolved issues related to its Dair Alzour complex and other locations.

The IAEA has long said a building destroyed at the complex was a nuclear reactor that should have been declared to the agency. Syria has said Dair Alzour is a non-nuclear site.

The complex was destroyed when it was bombed by Israeli jets in 2007. U.S. intelligence reports have said it was a nascent, North Korean-designed reactor intended to produce plutonium for nuclear bombs.