The Shiveluch volcano on Russia’s eastern Kamchatka peninsula erupted early on Tuesday and sent up a 10-kilometer ash plume, posing an increased threat to air traffic, the Kamchatka Volcanic Eruption Response Team (KVERT) told Reuters.

The team issued an aviation code red, noting that a “large ash cloud” was moving west of the volcano and that ash explosions up to 15 kilometers high could occur at any time. “Ongoing actions may affect international and low-flying aircraft,” the statement said.

Local authorities closed schools and ordered residents of nearby villages to stay at home, as the ash cloud spread tens of kilometers around the volcano, the head of the Ust-Kamchatsky municipal district Oleg Bondarenko said in a Telegram message.

Shiveluch, one of the largest and most active volcanoes in Kamchatka, has had about 60 significant eruptions over the past 10,000 years, with the last major eruption in 2007.