MOSCOW (AP) — A local official says one person has been killed and three injured after a bomb went off at the entrance of the local branch of Russia's main intelligence agency.

Governor Igor Orlov told Russian news agencies on Wednesday that an explosive device went off at the entrance of the FSB's office in the city of Akhangelsk in northern Russia. Three people have been hospitalized and one person has been killed.

Orlov also said authorities were boosting security measures at all public offices after the attack.

Russia's National Anti-Terrorist Committee confirmed the blast but would not immediately provide details.