A U.S. think tank says although North Korea has developed a small nuclear arsenal, it doesn’t seem to have the ability to deploy such weapons.

The Council on Foreign Relations made the assessment in a report titled, “U.S. Nuclear Weapons Policy.”

The report said North Korea detonated a low-yield nuclear device in October 2006, but it may not yet have the ability to deploy nuclear weapons.

The report added that efforts to stop countries such as North Korea from developing nuclear weapons will require aggressive diplomacy, and urged the US Obama administration to work closely with other countries.

In particular, even though North Korea halted its production of plutonium following active efforts by the members of the six-way nuclear talks, it is uncertain whether the communist state produced highly enriched uranium.

Uranium and plutonium are the two fissile materials that are needed to develop nuclear weapons.

Key U.S. experts on Korea Peninsula affairs took part in writing the report, including former Defense Secretary William Perry.