North Korea shipped coal to Russia last year that was then delivered to South Korea and Japan in a likely violation of U.N. sanctions, three Western European intelligence sources said.

The U.N. Security Council banned North Korean exports of coal last Aug. 5 under sanctions intended to cut off an important source of the foreign currency Pyongyang needs to fund its nuclear weapon and long-range missile programs.

But the secretive communist state has at least three times since then shipped coal to the Russian ports of Nakhodka and Kholmsk, where it was unloaded at docks and reloaded onto ships that took it to South Korea or Japan, the sources said.