China’s detention of four South Korean activists, which has continued for 50 days with no details being released, testifies again to its opaque legal system, which is far below international standards.

The case has also shown again Seoul’s passiveness in handling sensitive issues with Beijing.

It was a Seoul-based rights group that first revealed that the four had been detained since being arrested in the northeastern Chinese city of Dalian on March 29. The revelation on Monday apparently reflected the judgment that Seoul’s low-key approach would not lead to their early release.

China has provided no specifics regarding the detention except for a notice they were arrested on charges of endangering state security.

It has also virtually barred South Korea’s consular access to them, which is guaranteed under an international convention.

It was four weeks after their arrest that a South Korean diplomat met one of the detainees, Kim Young-hwan. Kim, a former leader of an underground leftist party, became an activist opposing Pyongyang’s regime after witnessing millions of North Koreans starved to death in the 1990s.

China has blocked consular access to the three others, claiming they presented written statements declining to see South Korean diplomats.

It is hard to believe they have decided to give up their rights to see South Korean diplomats out of their own free will. Seoul should confirm their true intentions in an independent way.

China is urged to allow the detainees all the rights stipulated in a related international convention.

We also believe it would be too much to apply the charges of endangering state security, which could be subject to life imprisonment, on the activists for probably contacting North Korean refugees in hiding to help their defection to South Korea or collect information on the situation in the North.

It can be suspected that the arrests, which coincided with China’s measure to send four North Korean defectors to Seoul, might have been made to soothe Pyongyang’s discontent.

Seoul’s Foreign Ministry says it has asked Beijing to handle the case in a fair and swift manner. It must do more than repeat this rhetoric to secure the early release of the detainees.