MOSCOW (AP) — Regional authorities in northwestern Russia say the Russian military has advised residents of a village near a navy testing range to move out following a rocket explosion that killed five nuclear engineers.

The Interfax news agency reported Tuesday that the regional administration based in Severodvinsk said a notice from the military recommended the evacuation due to unspecified activities at the test range.

Officials offered no further details about the advisory for the village of Nyonoksa.

Russia's state nuclear corporation, Rosatom, has said the engineers were killed Thursday while they were testing a "nuclear isotope power source" for a rocket engine.

Local authorities in Severodvinsk, a city of 183,000, reported a brief spike in radiation levels after the explosion, spooking residents. Officials insist it didn't pose any health hazards.