Moscow, Russia (CNN) -- Russian security forces killed eight militants that it said were connected to a 2009 terrorist attack, the head of Russia's domestic security and anti-terrorism agency said Saturday.
The Russian forces also detained 10 militants in connection with the 2009 attack, in a special operation in the southern Russian republic of Ingushetia earlier this week, the head of the Russian security agency said.
In a televised meeting on Russia's state media, Federal Security Service Director Alexander Bortnikov told Russian President Dmitry Medvedev that the operation happened on Tuesday and Wednesday.
Bortnikov said that "DNA tests of the militants have been carried out to establish their involvement" in a November 2009 Moscow to St. Petersburg train derailment that killed 28 people and injured about 90 others.
Following that attack, the Federal Security Service examined this "illegal armed group" in Ingushetia, Bortnikov said, "which was justifiably suspected of this crime."
"Investigative measures helped us obtain more materials confirming this theory," he said.
Among those killed in this week's operation was Alexander Tikhomirov, also known as Said Buryatsky, a prominent rebel leader in Russia's North Caucasus. Russian investigators link Tikhomirov to Chechen separatist leader Doku Umarov, who claimed responsibility for the 2009 train derailment.
According to the state-run RIA Novosti and ITAR TASS news agencies, Bortnikov said that police found an explosives laboratory and seized more than a ton of explosives -- including small arms and ammunition -- at the site of this week's special operation in Ingushetia.
Bortnikov said the site was in Ekazhevo, a village in Ingushetia's Nazran district.
State-run news media reports link Buryatsky's group to other large-scale attacks, including an assassination attempt on Ingushetia's president, Yunus-Bek Yevkurov, in June 2009 and a suicide bombing that killed at least 20 policemen in Ingushetia last August.
CNN's Amir Ahmed contributing to this report.