Indonesia raised the alert level on Thursday for the Mount Agung volcano on the tourist island of Bali following an increase in volcanic earthquakes.

The National Disaster Mitigation Agency said the alert has been raised from normal to vigilance.

The country’s geological agency recommends villagers and visitors stay further than 3 km from the mountain’s crater. The surrounding Karangasem district, an area of about 840 sq km, has a population of 408,000.

The disaster agency said the volcano last erupted in March 1963, killing some 1,100 people and hurling ash as high as 10 km.

It warned against panic, saying there would be further increases in volcanic activity and changes to the alert level before an eruption.

The Indonesian archipelago straddles the Pacific “Ring of Fire” and is prone to earthquakes and volcanic eruptions.