Indonesian authorities ordered the evacuation of thousands of people on Thursday after the successive explosions of Ruang Volcano in North Sulawesi Province. Intense volcanic activity has prompted a tsunami warning, while tons of volcanic ash and rock are being thrown.

According to Indonesia’s Center for Volcanology and Geological Disasters – which raised the alert level at the highest level IV– Ruang has exploded at least five times in the previous 24 hours.

The repeated eruptions have raised concerns about part of the volcano collapsing into the sea, thus causing a tsunami.

That prompted authorities to order the evacuation of more of 11,000 people from regions surrounding the volcano, including areas of Tagulandang Island, home to more than 22,000 people.

Tourists and residents have been asked to remain alert and not enter a 6km radius around the volcano’s active crater. The nearest international airport in the city of Manado has been closed for 24 hours as large plumes of smoke and ash continued to be billowed from the volcano.