A volcano on the Indonesian island of Sumatra erupted for the first time in 400 years yesterday, spewing a vast cloud of smoke and ash into the air and sending thousands of people fleeing from their homes.

Indonesia issued a red alert after the Sinabung volcano erupted, blanketing the area in thick and acrid black smoke, disaster officials said, although no casualties have yet been reported.

“It’s clearly dangerous so we’ve raised the warning to the highest level, or red level,” said the spokesman who is the head of the nation’s volcano disaster alert centre.

“From the crater, it shot smoke and volcanic ash 1,500 metres into the sky,” he said.

The 2,460-metre Sinabung in northern Sumatra has not erupted for more than 400 years but had shown “some volcanic activity” since Friday, the spokesman said, adding that they were monitoring the situation.

Villagers said they saw lava emerge from the crater around midnight, about 15 minutes before the eruption.

“I saw flames flickering, very red right at the top. Previously there was only smoke,” Terkilin Sembiring was quoted as saying by Detikcom news website.

“At the time, we heard a sound like an aircraft flying past. We thought it was a government official’s plane but it turned out that the sound came from the volcano,” another villager Maslin Pandia was quoted as saying by Kompas.com news website.

Television footage showed black smoke shooting up into the sky and lava overflowing from the crater as residents fled the area in pickup trucks and cars.

More than 18,000 people have been evacuated from several affected villages to towns outside a six-kilometre “danger zone”, officials said.

“The ash has spread to a distance of 30 kilometres from the volcano. Many of the villagers evacuated were farmers and they said the ash had settled on their vegetable farms,” search and rescue team official Mohammad Agus Wibisono said.

There were, however, no flight disruptions, Mr Wibisono said.

Disaster Management Agency spokesman Priyadi Kardono said that many residents in four affected villages at the foot of the volcano had fled immediately after the eruption.

“Many had left their homes even before they were evacuated. They said the volcano was spewing thick black smoke, small stones and sulphur.