JAKARTA - Mount Lewotobi Laki-laki volcano in Indonesia's East Nusa Tenggara province erupted on Wednesday, spewing a column of ash up to 5 km high and prompting the highest aviation alert, the country's Volcanology and Geological Disaster Mitigation Center said.

The volcano, located on Flores Island, 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 6,000 meters near the volcano. Airlines were also advised to anticipate possible disruptions caused by volcanic ash.

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Authorities warned communities on the slopes of the volcano, as well as tourists and visitors, not to conduct any activities within a 6-km radius of the crater. They also cautioned of potential lava floods along rivers originating from the peak during heavy rains.

Residents in areas affected by the ash fall were advised to wear masks or cover their noses and mouths to protect against respiratory hazards.

Indonesia has 127 active volcanoes.