A confidential United Nations report, whose details were confirmed to German news agency DPA, said Monday that North Korea is making progress in developing nuclear weapons.
Diplomatic sources said, quoting the report, that North Korea may have developed small nuclear devices for the warheads of its ballistic missiles.
The report on compliance with the sanctions imposed on North Korea confirmed that the assessments were based on information from a UN member country.
He stressed that North Korea continues its nuclear program, including the production of highly enriched uranium and the construction of a pilot light-water reactor.
North Korean governor Kim Jong-un's pursuit of nuclear weapons is said to be no secret, as Kim made clear in a speech a few days ago that he considered his country's nuclear arsenal as a security guarantee.