TOKYO (AFP) - Japan has reported a suspected sanctions breach to the UN Security Council after observing an apparent cargo transfer between a Dominica-registered oil tanker and a North Korean ship, the Foreign Ministry said on Wednesday (Jan 24).

A Japanese patrol spotted the tankers alongside each other in the East China Sea on Saturday night, the ministry said in a statement.

"Following a comprehensive analysis, the government strongly suspects they were transferring goods, which is banned by UN sanctions," it said, releasing a photo of the ships.

It identified the North Korean tanker as the Rye Song Gang 1, one of the vessels denied international port access by the Security Council.

The other tanker was named as the Yuk Tung, which has a gross tonnage of 20,200 tonnes.

The UN has blocked a total of eight ships suspected of carrying, or of having transported, goods banned under the sanctions on North Korea.

The UN has imposed a long series of sanctions on the North aimed at pressuring it to abandon its missile and nuclear programmes.

South Korea last month seized two ships suspected of transferring oil products to North Korea.

China has rejected accusations that it helped Pyongyang circumvent sanctions after US President Donald Trump claimed on Twitter that Beijing was turning a blind eye to oil transfers to its neighbour.

Russia has denied similar US accusations.