In what appears to be a lax enforcement by China of UN sanctions, North Korean vessels — some carrying illicit coal shipments — were anchored in Chinese waters last year, according to photos from a UN report published on Friday.

Key points: The annual report says North Korea continues to flout council resolutions "through illicit maritime exports"

The annual report says North Korea continues to flout council resolutions "through illicit maritime exports" The report says illegal exports earn Pyongyang hundreds of millions of dollars

The report says illegal exports earn Pyongyang hundreds of millions of dollars China's foreign ministry says China has always implemented UN sanctions

In one photo dated October 10, eight North Korean vessels are anchored off the Chinese port of Ningbo-Zhoushan.

The UN sanctions — aimed at curbing Pyongyang's nuclear program — require countries to inspect cargo destined for or coming from North Korea that is within their territory or being transported on North Korean-flagged vessels.

The annual report to the UN Security Council by independent sanctions monitors said North Korea continued to flout council resolutions "through illicit maritime exports of commodities, notably coal and sand" in 2019, earning Pyongyang hundreds of millions of dollars.

A UN Security Council diplomat, speaking on condition of anonymity, said China had the capacity to stop sanctions busting by its ally North Korea but "is simply choosing not to implement the Security Council resolutions".

In a photo dated October 10, eight North Korean vessels are anchored off the Chinese port of Ningbo-Zhoushan. ( Reuters: United Nations/Handout )

"According to a Security Council member, Chinese warships have received notification in real time on multiple occasions of vessels entering its territorial waters who have been observed to be in violation of the UN Security Council resolutions," the diplomat said.

China's policing of neighbour North Korea's adherence to UN sanctions, first put in place in 2006, is considered crucial to the effectiveness of the measures, spearheaded by the United States and unanimously adopted by the Security Council.

In February, the sanctions monitors report found North Korea continued to enhance its nuclear and ballistic missile programs last year.

China says it 'earnestly fulfils' international obligations

More photos in the report show floating cranes supporting "illicit ship-to-ship coal transfers". ( Reuters: United Nations/Handout )

When asked if China had received the notifications and acted on them, the office of the spokesperson at the Chinese foreign ministry said in a statement on Thursday that China implemented UN sanctions.

"China has always earnestly fulfilled its international obligations and dealt with relevant issues in accordance with the resolutions," it said.

"The report clearly states that this is information provided by 'a member state' and not the opinion of the expert group."

North Korea's mission to the United Nations in New York did not immediately respond to a request for comment.

A second photo from the UN report shows 10 North Korean vessels anchored in Chinese waters on September 15 last year near the port of Lianyungang. The photos were provided to the UN sanctions monitors by an unidentified member state.

A photo from the report shows 10 North Korean vessels anchored in Chinese waters on September 15 last year near the port of Lianyungang. ( Reuters: United Nations/Handout )

The monitors reported that North Korea conducts ship-to-ship transfers of illicit cargo such as coal, which has been banned since 2017 in a bid to cut off funding to Pyongyang.

More photos in the report show floating cranes supporting "illicit ship-to-ship coal transfers".

Under UN sanctions imposed in 2017 all countries were also required to repatriate North Koreans working abroad by the end of last year to stop them earning foreign currency for leader Kim Jong-un's Government.

A senior US official in January accused China of failing to send home all North Korean workers.

The United States has said it believed Pyongyang was earning some $500 million a year from nearly 100,000 workers abroad, 50,000 of whom were in China.

In a March 20 letter to the council's North Korea sanctions committee, China — which requested that its note remain private — said it had completed the repatriation by the December 22 deadline.

"China will continue to implement Security Council resolutions and fulfil its international obligations," China's UN Ambassador Zhang Jun wrote in the note, seen by Reuters.

ABC/wires