VLADIVOSTOK, September 30. /TASS/. A court in Russia’s Far Eastern city of Nakhodka ordered custody for four more North Korean fishermen who attacked Russian border guards in the Sea of Japan, a spokesperson for the court told TASS on Monday.

Earlier the court ordered a two-month arrest for the first group of six fishermen.

"A pre-trial restriction measure has been chosen for four North Korean citizens such as custody during the period of conducting a preliminary investigation," the spokesperson said.

As of Monday, a total of ten North Koreans have been arrested as part of the investigation into the attack.

According to Russia’s Federal Security Service, on September 17 Russian border guards spotted two North Korean schooners and 11 motorboats poaching in Russia’s exclusive economic zone near Yamato Bank in the Sea of Japan. The crew of one of the vessels staged an armed attack on the Russian border guards, injuring four of them. One of them received gunshot wounds. The FSB said the border guards’ life was not in danger. On September 20, the schooners and the crew were taken to the port of Nakhodka.

A total of 161 North Korean citizens have been detained. Some of them were injured and were provided with medical assistance, and one person died.

The Russian Investigative Committee launched a criminal case into the attack on the border guards.