Volcanic ash from an eruption of Eurasia's highest volcano, Klyuchevskoi, on the Kamchatka Peninsula in Russia's Far East, is stretching over 500 km above the Bering Sea, a local volcanology institute spokesman said Monday.

Satellite data show a distinct ash cloud northeast of the volcano at a height of 8.2-8.7 km, which started to erupt on February 15. Although the ash cloud is making monitoring almost impossible, seismic reports suggest that the eruption could escalate.

"Ash is a hazard to aircraft flying into the ash cloud above the Bering Sea," the source said. "Ash particles with a diameter of up to 2mm can destroy engines if they get into turbines."

Ash is reportedly falling 40 km away from the volcano, and locals have reported hearing powerful explosions. Nearby villagers have been advised to leave their homes only in emergencies to prevent intoxication and other negative consequences.

Prior to February's volcanic activity, Klyuchevskoi last came to life in January-May 2005. Following that eruption, the volcano "sank" by 50 meters (about 165 feet), from 4,800 meters (about 16,000 feet) to the current 4,750 meters (15,845 feet).

Apart from powerful mud flows that could form from ice thawing on the volcano's sides, the current eruption of Klyuchevskoi does not pose a threat to locals.