Two fishermen detained by Estonian border guards after their boat crossed onto the Estonian side are both former KGB officers, Russian news website 47news.ru said.

The two men resisted arrest by Estonian authorities and attempted to flee back to the Russian side on Saturday, but border guards managed to take them to a Jõhvi jail, detaining them for resisting arrest and illegal border crossing. They are still currently in an Estonian pretrial detention center under a September 22 warrant.

The two men, Mihhail Suhoshin, 64,and Alexander Ladur, 54, are both believed to have held the rank of major in KGB, the Soviet secret service, and later worked for FSO (Federal Protective Service) but are now retired, the website said, adding that the arrests could be an Estonian retaliation for the arrest of ISS official Eston Kohver earlier in September.

"On the Narva River, the temporary border line is marked with special buoys with a short distance between them and the border is very visible. There are relatively few accidental illegal border crossings. Resistance to border guards is encountered extremely rarely," said a police and border guard spokesperson on Saturday.