Indonesia has raised flight warnings around the Mount Sinabung volcano to their highest level after it sent a plume of ash more than 7km (4.4 miles) into the air, turning day into night for people nearby.

Areas around the crater of the volcano, located about 1,900km north-west of the capital, Jakarta, on the island of Sumatra have been off-limits for several years because of frequent volcanic activity.

The Australian weather bureau’s Volcanic Ash Advisory Centre (VACC), in the northern city of Darwin, issued maps on Monday showing the ash cloud spreading north, north-west and south-south-east. Indonesia also upgraded its Volcano Observatory Notice for Aviation (Vona) to red, its highest warning, and said the ash-cloud top had reached 23,872 feet (7,276 metres). inabung is about 75km south-west of Kualanamu international airport in Medan.

Nur Isnin Istianto, head of the regional airport authority, said Kutacane airport in Aceh province had been closed, but the wind direction allowed the airport of Kualanamu, Meulaboh and Silangit to remain open.

Sutopo Purwo Nugroho, a spokesman for Indonesia’s Disaster Agency, said the eruption began on Monday morning, accompanied by multiple earthquakes and showering surrounding villages with small rocks. “In five districts it became dark with a visibility of about five metres,” he said.

No casualties were reported.

The agency urged the public to stay out of a 7km exclusion zone around the crater and watch for further warnings, which could cover floods. The 2,460-metre tall volcano is among Indonesia’s most active.

When Sinabung erupted in 2014 more than a dozen people were killed and thousands were evacuated. Its last known active period had been four centuries earlier.