The 267-page report, obtained Saturday by The Associated Press, also accused North Korea of importing luxury vehicles, watches and liquor and other sanctioned items including robotic machinery, and continuing to illegally access international banking channels "mainly by using third party intermediaries."

The U.N. Security Council has imposed increasingly tough sanctions against the Democratic People's Republic of Korea, the country's official name, including banning most of its exports and severely limiting is imports, to pressure Pyongyang to abandon its nuclear and ballistic missile programs.

The full report by the panel of experts monitoring the sanctions provides more details to the summary and some excerpts reported by AP in February. It includes photos of ballistic missile launchers, nuclear sites and vessels recommended for blacklisting.

The panel made 39 recommendations to the Security Council, including on the blacklisting of 14 vessels.

It said one vessel is registered in Sierra Leone and six were previously registered in the West African nation. Two are North Korean, one is Chinese, one Vietnamese, one was formerly registered in Togo, one was formerly registered in St. Kitts and Nevis, and the flag of one is unknown.

China has been neighboring North Korea's largest trading partner and has been considered critical to enforcing U.N. sanctions.

The panel said the Chinese-flagged Yun Hong 8 — which it recommended for sanctions — made at least 10 port calls between February and October 2019 at the North Korean port of Nampo and delivered refined petroleum. It was also observed during that period receiving refined petroleum from other foreign-flagged vessels, which an unidentified U.N. member state said was likely for delivery to the DPRK, the experts said.

China responded to the panel's inquiry about the vessel by questioning "the serious lack of accuracy of the relevant information," the report said.

China's Foreign Ministry and U.N. ambassador have said the country is implementing the sanctions.

A photo in the report provided by an unnamed U.N. member state shows multiple coal-laden DPRK-flagged vessels at anchor near Lianyungang, China, which the panel said is being used to conduct ship-to-ship coal transfers. The panel said it is investigating a Vietnam-flagged vessel, the Phuong Linh 269, suspected of delivering coal originating in North Korea to the Chinese port of Qisha on multiple occasions.

Despite a U.N. ban, the panel said North Korea's coal exports increased in 2019. It cited an unnamed member state saying the DPRK exported 3.7 million tons of coal between January and August 2019, with an estimated value of $370 million.

The Security Council also banned the export of earth and stone, which includes sand.

The panel said an unidentified member state reported that a substantial sand-export operation from the DPRK to China has been carried out since May 2019 with over 100 illicit shipments involving at least 1 million tons of sand worth at least $22 million.

"China responded that it attached great importance to the clues provided by the panel in relation to the smuggling of sand originating in the Democratic People's Republic of Korea," but was unable to confirm that the sand had been transported to Chinese ports, the report said.

As for the import of refined petroleum products, which is limited 500,000 barrels annually, the panel said the addition of larger foreign-flagged tankers delivering to the DPRK has expanded its illicit imports. It said an unidentified member state calculated that in the first 10 months of 2019, "foreign-flagged tankers alone had made a total of 64 deliveries, amounting to between 560,000 and 1.531 million barrels of refined petroleum products."

The panel said North Korea has also continued to transfer fishing rights in violation of sanctions, which earned the country $120 million in 2018, according to an unnamed member state.

Under a 2017 sanctions resolution, all DPRK nationals working overseas were to be repatriated by Dec. 22, 2019.

In China, Russia and elsewhere, there is strong demand for cheap North Korean workers. The U.S. State Department previously estimated there were about 100,000 North Korean workers worldwide, and civilian experts said those workers brought the DPRK an estimated $200 million to $500 million in revenue a year.

The report said "in multiple cases, workers were not repatriated to the Democratic People's Republic of Korea but moved to a third country."

The panel said an unnamed member state alleged that 2,000 North Koreans "recently entered China on visitor visas for the purpose of earning income." In response to its inquiry, the panel said China replied that it could not verify the allegation.

On individual cases, the experts said North Korean soccer player Han Kwang Song, who joined the youth wing of Italy's Juventus Football Club in 2019, joined the Qatari team al-Duhail in January, and Choe Son Hyok has been playing for Italy's Societa Sportiva Arezzo since 2018. Austria reported that it had initiated procedures to revoke the work permit of Pak Kwang Ryong, who has played for Sportklub Niederösterreich St. Pölten since 2017.

As for cyber attacks, the panel said North Korea is becoming "increasingly sophisticated" in targeting both financial institutions and cryptocurrency exchanges, which deal in virtual money like bitcoin, Ethereum and Ripple.

Last August, the panel said North Korean cyber experts illegally raised money for the country's weapons of mass destruction programs "with total proceeds to date estimated at up to $2 billion."

In the new report, the panel cited a U.S. court document in which Virgil Griffith, an American who spoke at an April 2019 "cryptocurrency conference" in Pyongyang, said organizers told him that "during his presentation, (he) should stress the potential money laundering and sanction evasion applications of cryptocurrency and blockchain technology."