North Korea and China are reportedly no longer trying to hide their illicit coal trade, in open violation of UN sanctions on Pyongyang.  

According to a Wall Street Journal report on Tuesday, which cites U.S. officials and satellite photos, North Korea-flagged ships were seen transporting hundreds of coal shipments to China's Ningbo-Zhoushan region over the past year. It said China-flagged cargo ships were also spotted in North Korea to collect coal from the port of Nampo. 

North Korea has used various sanctions evasion techniques for years, such as ship-to-ship transfers from the sea to ships or using foreign-flagged ships.    
 
The WSJ quoted a senior U.S. Department official as saying that North Korea is now exporting coal to China without making any particular effort to hide or disguise.  

The U.S. government estimates North Korea made about 400 billion won by smuggling coal to China in the first nine months of this year, according to the report.