South Korea’s intelligence agency says Japan is not taking appropriate measures against several cargo ships suspected of violating UN Security Council sanctions on North Korea. 

According to the Chairman of the National Assembly Intelligence Committee, the National Intelligence Service(NIS) evaluated Tokyo’s related measures during a committee meeting on Tuesday.  

The NIS said that, despite South Korea’s sharing of related information, Japan is allowing repeated entries and departures of three suspected vessels, citing Tokyo's lack of a domestic legal foundation to deal with such cases. 

The South Korean intelligence agency said Japan's reaction is tepid and passive compared with U.S. measures on vessels implicated in similar cases. 

It's not known how the vessels violated the UN sanctions.