Russia has condemned what it called an influx of Japanese fishing trawlers it says are intruding in its territorial waters. But Moscow says it will release two Japanese fishermen detained this month near the disputed Kuril Island chain.

Russia's Foreign Ministry, in a statement Tuesday, called the presence of Japanese trawlers in the area a "mass intrusion." It said 39 trawlers entered Russian waters on Sunday, and said the ministry had summoned Japan's ambassador to Moscow to hear a strong protest.

Despite the protest, Moscow says it will free on Wednesday two of three Japanese crewmen seized on illegal fishing charges August 16. The boat's captain remains in custody and is to go on trial September 7.

Russian forces seized the Kurils at the end of World War II, but Japan still claims the four small islands in the northwestern Pacific.

The ongoing dispute has kept Moscow and Tokyo from signing a formal peace treaty ending the war.

Some information for this report was provided by AFP and Reuters.