Image copyright Reuters

A volcano has erupted on the Indonesian island of Sumatra, engulfing villages in ash and killing at least 14 people.

Mount Sinabung spewed hot gas, ash and rocks 2km (1.5 miles) into the air in a series of eruptions during the morning.

Emergency official Sutopo Purwo Nugroho said three schoolchildren and a teacher were among the dead.

Thousands were evacuated in September when Sinabung erupted after being dormant for three years. Many were allowed back to their homes on Friday.

Officials fear there may have been more casualties, but they cannot get closer because of the heat from the eruption.

Pictures taken at the scene showed rescue workers recovering bodies that were buried in ash.

Image copyright AFP Image caption Saturday's eruption was the worst since Sinabung came back to life in 2010, after 400 years dormancy

Image copyright AFP Image caption Experts say the mountain is more difficult to predict than other more closely studied mountains

When the volcano erupted in 2010, at least two people were killed and 30,000 others were displaced.

Before 2010, Sinabung had not erupted in 400 years.

It is one of about 130 active volcanoes in Indonesia.

Experts say Sinabung has been studied less than more active volcanoes, making it more difficult to predict.

Image copyright AP Image caption For the past five months, Indonesians have become accustomed to eruptions from Sinabung