A North Korean ferry suspected of involvement in illicit trade has again canceled a Niigata port call, citing tightened security by Japanese authorities, a group of pro-Pyongyang Korean residents in Japan said Monday.

It was the second time this month that a visit by the Mangyongbong-92 was called off. The General Association of Korean Residents in Japan (Chongryun) said North Korea told it Friday of the cancellation of Monday's visit.

Chongryun quoted North Korean officials as saying they could not expect the situation in Japan to improve.

"Ships using the port must be treated equally. We regret that only the Mangyongbong-92 is under political pressure," a Chongryun official said, referring to the beefed-up security measures put in place for the ferry.