Nuclear security

Where are the world's nuclear weapons?

North Korea is believed to have developed nuclear weapons capability, but there is a high degree of uncertainty around whether the nation has actually built weapons. However, there is no disagreement it has produced fissile material that could be turned into a nuclear weapon.

The United States believes that North Korea will be able to launch a reliable nuclear-capable intercontinental ballistic missile by early 2018, a US official familiar with the latest intelligence assessment confirmed to CNN in July.

Hans Kristensen, director of the Nuclear Information Project at the Federation of American Scientists, told CNN via email that the "the intelligence assessment is that they have produced sufficient fissile material sufficient to potentially build 30-60 warheads, not that they necessarily have built that many operational weapons."

Other experts said they think that number is on the high side.