Russia’s Federal Security Service said on Friday that a gunman killed two people in an attack on one of its regional offices in the far east of the country.

The gunman burst into the office in the Khabarovsk region, which is close to China and opened fire, killing one of its employees and a visitor, FSB said.

Another visitor was injured in the attack, the successor organization to the Soviet KGB said, adding the attacker had been killed.

The gunman identified as A.V. Konev was a local resident, born in 1999, who belonged to an unnamed nationalist group, the TASS news agency reported, citing an FSB official.

Russia was this month shaken by the deadly suicide bombing of the St. Petersburg metro, which killed 16 people.

A woman wounded in the bombing died in hospital Thursday, a local official said, taking the death toll from the attack to 15.

Another 23 people are still in hospital, four of them in serious condition, she said.

Authorities say the attack was carried out by 22-year-old suicide bomber Akbarjon Djalilov, a Russian national born in Kyrgyzstan.

Ten men from Central Asia have been detained in connection with the bombing, including Kyrgyz-born Abror Azimov, whom officials say was one of the organizers.

Both he and his elder brother Akram — whom the FSB says was allegedly in contact with global terror groups — are in custody.

There has been no claim of responsibility but investigators are looking into possible links to ISIS jihadists, who have threatened to strike Russia in revenge for its intervention in Syria.