A volcanic eruption on a remote Russian island north of Japan has created a giant ash cloud that threatens passing airplanes, the RIA-Novosti news agency reported on Sunday, citing Russian geologists.

The eruption of Sarychev Peak on uninhabited Matua Island, part of the Kuril Islands archipelago in the north Pacific Ocean, began overnight Thursday-Friday and is still underway, the news agency said.

It has formed an ash cloud eight kilometres (five miles) high which has spread 310 kilometres to the west, Olga Shestakova, a spokeswoman for the Marine Geology and Geophysics Institute of the Russian Academy of Sciences, was quoted as saying.

"Information on the eruption has been sent to organisations dealing with the safety of airplanes and ships, as the ash cloud presents a threat to airplane engines and may lead to communications systems failures," Shestakova said.

Sarychev Peak is one of the most active volcanos on the Kuril Islands, a seismically active archipelago that runs northeast from Japan's Hokkaido Island to Russia's Kamchatka Peninsula.

The southernmost four islands in the archipelago are disputed between Russia and Japan, but Matua Island, where the volcano is located, is agreed to be Russian territory. It is called Matsuwa Island by the Japanese.