ARKHANGELSK, October 31. /TASS/. One person has been killed and three were hospitalized following an explosion inside the building of the Federal Security Service’s (FSB) Directorate for the Arkhangelsk Region, Arkhangelsk Region Governor Igor Orlov told journalists on Wednesday.

"Three people are staying in the hospital. <...> One person was killed; he is being identified," he said.

According to the governor, the explosion occurred inside the building. "A crime with the use of an unidentified explosive device was committed. <...> The type of the explosive device is being identified, and all the necessary actions to determine the causes and results of this tragic incident are being carried out," he said, specifying that security measures were tightened in regional facilities.

The explosion occurred on Wednesday morning inside the FSB Directorate for the Arkhangelsk Region. Law enforcement authorities are working on the site and examining it. Traffic was partially restricted for vehicles and pedestrians. The building is located in the city center, not far from a drama theater and large shopping malls.