Two volcanoes have erupted on Russia's far-eastern Kamchatka Peninsula, tossing massive ash clouds miles into the air, forcing flights to divert and blanketing one town with thick, heavy ash.
The Klyuchevskaya Sopka, Eurasia's highest active volcano, exploded along with the Shiveluch volcano, 45 miles to the north-east, the Russian Emergency Situations Ministry's branch in Kamchatka said, adding that flights in the area had to change course.
Ash clouds from the remote volcanoes billowed up to 33,000ft and were spreading east across the Pacific Ocean, vulcanologist Sergei Senyukov told Rossiya 24 television. Streams of lava flowed down the slopes of Shiveluch.
The US Federal Aviation Administration today issued a notice to pilots that they should remain alert for possible ash clouds, saying emissions have "intermittently complicated air travel" in the area of the Kamchatkan Peninsula.
"Any air carriers, including foreign air carriers, that observe or experience any difficulties resulting from an encounter with volcanic ash, please notify air traffic control immediately," the notice said.
Several pilots reported seeing ash clouds in the Alaskan region, FAA spokeswoman Laura Brown said. However, the ash has been below 25,000ft, while planes are assigned altitudes above that level so there was no difficulty, she said.
So far FAA has not issued any flight restrictions due to ash, she said.
Kamchatka volcanoes are part of the "Ring of Fire" string of volcanoes encircling the Pacific. It was not clear whether the volcanic activity on Kamchatka was related to Tuesday's eruption of the Mount Merapi volcano in Indonesia that killed 33.