The U.N. Security Council's sanctions committee on North Korea has concluded that Pyongyang appears to have "deliberately breached" a contract with a Chinese company by converting Chinese lumber transporters into missile launch transporters, according to a U.N. report on Wednesday.

The 16-wheel missile launch transporter was seen at North Korea's military parade in April last year, raising concerns that the vehicle's design and technology might have come from China. If so, it would be a violation of U.N. resolutions that ban member states from selling "all arms and related materials" to the North.

In its annual report, the Security Council's North Korea Sanctions Committee Panel of Experts said, citing a Chinese briefing to the committee in October last year, the Chinese company named Hubei Sanjiang Space Wanshan Special Vehicle Co. exported six lumber transporters to North Korea in 2011.

China told the committee that, "These vehicles had a substantive distinction from transporter-erector-launchers or missile transporters and could not be used for transporting or launching missiles," according to the annual report.

The North's Forestry Ministry Rim Mok General Trading Co. signed a contract to buy the six vehicles worth 30 million yuan (about $4.9 million) from the Chinese company.

According to the contract, North Korea said the vehicles would be used for "transporting the timbers in the Democratic People's Republic of Korea (North Korea)."

Citing an image analysis conducted by the U.N. Institute for Training and Research Operational Satellite Applications Program, the North Korean missile vehicles and the Chinese vehicles named "WS51200" match in terms of their "fronts and sides, the fenders, the exhaust systems, fuel tanks and tires," the U.N. report showed.

"On the basis of the information currently available, the panel considers it most likely that the Democratic People's Republic of Korea deliberately breached the end user guarantee that it officially provided to Wuhan and converted the WS51200 trucks into transporter-erector-launchers," it said.

North Korea, which has conducted three nuclear tests since 2006, has been hit by a series of U.N. sanctions.

The U.N. panel said the U.N. sanctions have delayed the North's development of missile and nuclear arsenal.

"Overall, the panel believes that while the imposition of sanctions has not halted the development of nuclear and ballistic missile programs, it has in all likelihood considerably delayed the timetable of the Democratic People's Republic of Korea, through the imposition of financial sanctions and the bans on the trade in weapons has choked off significant funding which would have been channeled into its prohibited activities," it said.

"In both its imports and exports, the Democratic People's Republic of Korea continues to use a variety of techniques to circumvent national controls, indicating that the imposition of sanctions has hampered its arms sales and illicit weapon programs."

The U.N. report, the third of its kind since 2010, also recommended putting additional North Korean individuals and entities related to the North's nuclear and ballistic missile program on the list of sanctions against North Korea.

In a brief statement, South Korea's foreign ministry said the latest report "is expected to contribute to the international community's effective implementation of the U.N. Security Council resolutions on North Korea."

"(South Korea) will further strengthen coordination with the international community for the effective implementation of sanctions against North Korea," it said. (Yonhap News)