North Korea appears to be engaging in illegal ship-to-ship transfers not only in the Yellow Sea but also the East Sea. 

According to the Voice of America(VOA) on Thursday, satellite imagery taken by Airbus in late March and released by Google Earth recently shows two vessels side by side in waters off North Korea's eastern port city of Wonsan. 

One of the vessels is loaded with black objects in the cargo area while a crane from the other ship is seen extending over the cargo area.

The VOA said the two vessels appeared to be conducting an illegal ship-to-ship transfer of coal, noting that they were carrying out difficult work in the middle of the sea even though there are docks nearby. 

Previously, the expert panel assisting the UN Security Council’s North Korea Sanctions Committee said the sites for North Korea's illegal ship-to-ship transfers were being moved from the South China Sea and East China Sea to the western waters of North Korea last year and this year.

The VOA said the East Sea has been drawing attention recently amid deepening ties between North Korea and Russia.