North Korea violated UN sanctions last year by shipping coal to Russia which was then delivered to South Korea and Japan, Western European intelligence sources said.

The UN Security Council banned North Korean exports of coal on August 5 under sanctions intended to cut off an important source of foreign currency Pyongyang needs to fund its nuclear weapon and missile programmes.

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

A U.S. security source also confirmed the coal trade via Russia and said it was continuing.

North Korea violated UN sanctions last year by shipping coal to Russia. The UN security council created sanctions intended to cut off an important source of foreign currency Pyongyang needs to fund its nuclear weapon and missile programmes

Asked about the shipments, a U.S. State Department spokesman said: 'It's clear that Russia needs to do more. All UN member states, including Russia, are required to implement sanctions resolutions in good faith and we expect them all to do so.'

A State Department official added: 'There is no more time for excuses. The world is watching Russia's actions closely.

'Russia says it wants better relations with the United States, so Moscow should prove that by cooperating with us, not working against us, on this urgent threat to all nations.'

Two separate routes for the coal were identified by the Western security sources.

The first used vessels from North Korea via Nakhodka, about 53 miles (85km) east of the Russian city of Vladivostok.

One vessel that used this route was the Palau-flagged Jian Fu which Russian port control documents show delivered 17,415 tonnes of coal after sailing from Nampo in North Korea to LLC Port Livadiya in Nakhodka.

Another ship at the same port loaded 20,500 tonnes of coal and headed to the South Korean port of Ulsan, according to Russian port control documents.

Two separate routes for the coal were identified by the Western security sources. The first used vessels from North Korea via Nakhodka (Pictured: Livadiya Port in Nakhodka)

Reuters was unable to reach the operator of the Jian Fu, which was listed in shipping directories as the China-based Sunrise Ship Management. The Nakhodka-based transport agent of the Jian Fu did not respond to written and telephone requests for comment. LLC Port Livadiya did not respond to a written request for comment.

A European security source said: 'Russia's port of Nakhodka is becoming a transhipping hub for North Korean coal.'

The second route took coal via Kholmsk on the Russian Pacific island of Sakhalin, north of Japan.

The Rung Ra 2 docked in Kholmsk three times between August 1 and September 12, unloading a total of 15,542 tonnes of coal, while the Ul Ji Bong 6 unloaded a total of 10,068 tonnes of coal on two separate port calls according to the official Russian Information System for State Port Control.

The coal did not pass Russian customs because of the UN sanctions taking effect, but was then loaded at the same dock onto Chinese-operated vessels. Those vessels stated their destination in Russian port control documents as North Korea, according to a source in Sakhalin port administration who spoke on condition of anonymity.

Asked to respond to the report, Kremlin spokesman Dmitry Peskov said on Friday that Russia abided by international law.

The second used the port in Kholmsh (pictured). A State Department official said: 'Russia says it wants better relations with the United States, so Moscow should prove that by cooperating with us, not working against us, on this urgent threat to all nations'

Mr Peskov told reporters on a conference call: 'Russia is a responsible member of the international community.'

The U.S. Treasury put the owner of one of the ships, the UAL Ji Bong 6, under sanctions for delivering North Korean coal to Kholmsk on September 5 on Wednesday.

Asked about the shipments identified by Reuters, Matthew Oresman, a partner with law firm Pillsbury Winthrop Shaw Pittman who advises companies on sanctions, said: 'Based on these facts, there appears to be a violation of the UN Security Council resolution by the parties involved.

'Also those involved in arranging, financing, and carrying out the shipments could likely face U.S. sanctions.'

The United States has led efforts to toughen UN sanctions to force North Korea to give up development of nuclear missiles capable of hitting America.

In Beijing on Friday, foreign ministry spokeswoman Hua Chunying told reporters she did not know anything about the situation but China was clear in its hope that the UN resolutions are followed fully.

China will not allow any Chinese company or individual to do anything that goes against the resolutions and if there is cast-iron proof this is happening, China will handle it seriously and in accordance with the law, she added.