The eruption of Mount Sinabung volcano in western Indonesia has claimed lives of six people, an official said Sunday. Besides, three others are in critical condition after the highly active volcano erupted in the North Sumatra province sending ashes as high as 2 miles into the sky Saturday.

The ash rolled down the slopes as far as 3 miles westward into a river, National Disaster Management Agency spokesman, Sutopo Purwo Nugroho, said. The deceased and the injured were on their routine work at their farms in Gamber village, about 2.5 miles away from the slope, or within the danger area, which was reportedly declared off limits by officials for safety.

“Nine people were struck by the hot clouds. Six died, and three others remain critical with burns,” Nugroho told Agence France-Presse (AFP).

The hot gas and rocks, which move at a rapid speed, can reach 700 degrees celsius (1292 Fahrenheit) as they tumble down the sides of the volcano, he added.

Soldiers, police and disaster relief agencies, along with volunteers and villagers, launched a search operation for possible victims, the Associated Press reported, citing Nugroho. Images reportedly showed dead farm animals covered in dust.

Mount Sinabung, one of the 129 volcanoes in Indonesia, sits on the Pacific Ring of Fire, a seismic activity belt stretching around the Pacific Ocean basin. The volcano has been erupting at irregular intervals since 2010 after remaining inactive for over 400 years. In February 2014, an eruption at the volcano killed 16 people.