Indonesia has raised the alert level at one of its dozens of volcanos to its highest level, telling villagers and tourists to stay off the rumbling slopes.

Mount Bromo typically erupts once a year but — unlike nearby Mount Merapi — rarely spits debris and hot gas far from the crater and nearby towns are not considered to be in harm's way.

The government decided to raise Bromo's danger level after it started shooting ash into the air, the Ministry of Mines and Energy said in a statement. It warned that a bigger blast could still be on the way.

Bromo is one of Java island's most popular tourist attractions.

Villagers also climb the 7,641-foot (2,329-meter) mountain to leave offerings to spirits.

Indonesia is a vast archipelago of 235 million people that straddles the "Pacific Ring of Fire," a system of fault lines that leave it vulnerable to earthquakes and give it more active volcanoes than any other country.

Bromo is 170 miles (275 kilometers) east of Merapi, which in the past month has unleashed a series of powerful eruptions that have left more than 300 people dead.