Iran and North Korea have shared ballistic missile technology which China has blocked, diplomats said.
According to documents by Western journalist, the illicit technology passed through neighboring third country, is identified as China by diplomats. Beijing has not commented on the report, which includes accusations about the technology that was transferred aboard.
After two nuclear tests in 2006 and 2009 the U.N. Security Council imposed sanctions against North Korea. North Korea is also banned from dealing in nuclear and ballistic material.
Iran is also under international sanctions because of its uranium enrichment activities, which the United States and its allies suspect are weapons-related but they insist that the nuclear program is for peaceful purposes.
The U.N. report was submitted to the members of the Security Council. Chinese expert on the panel refused to sign on the new report, The New York Times reported.
The panel's findings were first reported by Reuters and the report said the warhead for the North's Nodong missile paraded through Pyongyang had a strong design similarity with the Iranian Shahab-3 triconic warhead.
In the past, both China and Russia have had attempted to block reports critical of North Korea, saying it amounts to impinging on the sovereignty of member countries.