Thousands flee Indonesia volcano on Sumatra Published duration 30 August 2010

media caption The BBC's Karishma Vaswani: ''The most immediate risk is that villagers will inhale fumes from the volcano''

Thousands of Indonesians have spent the night in emergency shelters after fleeing an erupting volcano on the island of Sumatra.

Officials issued a red alert after Mount Sinabung began to spew lava shortly after midnight (1900 GMT).

Smoke and ash reportedly shot 1,500m into the air. Witnesses said they could see the lava from several miles away.

Mount Sinabung, some 60km (40 miles) south-west of Sumatra's main city Medan, has not erupted for 400 years.

Officials from the Red Cross told the BBC that more than 19,000 people were being moved from the slopes of Mount Sinabung and surrounding areas.

Ash and acrid smoke from the volcano have blanketed villages and crops. Local people arriving at refuge centres were covered in grey ash, many had their faces covered.

At least one person is reported to have died from breathing problems.

The volcano had been pumping out smoke all day Saturday, but alert levels had not been raised, and local media reported that villagers had been taken by surprise.

The Medan Tribune quoted one local resident as saying he panicked and ran when he saw lava coming towards him "like a ball of fire".

Surono, head of the nation's volcano disaster alert centre, told AFP news agency that the alert level had been raised to red because the situation was "clearly dangerous".

"Initially we thought the ash and smoke were triggered by rain but now we know the driving pressure was from magma," he said.

He said that as the volcano had not erupted since 1600, scientists knew very little about it.