Hanoi (VNA) – Mount Lewotobi Laki-laki volcano in Indonesia's East Nusa Tenggara province erupted on October 1, spewing a column of ash up to 5 km high and prompting the highest aviation alert, the Indonesian Volcanology and Geological Disaster Mitigation Centre (VGDMC) said. The volcano sent thick gray ash clouds drifting to the west and northwest of the crater. A Volcano Observatory Notice for Aviation has been issued at the red level, the highest warning, banning flights below 6 km near the volcano. Residents in areas affected by the ash fall were advised to wear masks or cover their noses and mouths to protect against respiratory hazards. Standing 1,584 meters tall, Lewotobi Laki-Laki is one of the 127 active volcanoes in Indonesia, a country highly prone to earthquakes and eruptions because of its location on the Pacific Ring of Fire./.