Mount Lewotobi Laki-Laki erupted on Monday and Tuesday, killing nine people and forcing the relocation of residents from a 7-kilometre (4.3-mile) exclusion zone.

The country's volcanology agency reported seven eruptions on Thursday, the biggest of which belched an ash tower five miles (eight kilometres) high, according to an observation post.

Some said it was the biggest eruption they had ever seen from Lewotobi Laki-Laki.

"This is the first time I saw this big eruption since I've been living in Lewolaga village," said Anastasia Adriyani, 41, who lives outside the exclusion zone.

"I was cooking at the community kitchen (for evacuees) and when it happened, I ran back home. I was very scared."

Officials have raised the alert level for the 1,703-meter (5,587-foot) twin-peaked volcano on the tourist island of Flores to the highest level.

There were no immediate reports of damage to nearby villages from Thursday's fresh eruptions.

But residents and schoolchildren were seen running from their homes, according to an AFP journalist, who added volcanic lightning was also seen.

Locals at a temporary shelter were anxious as the latest eruptions rumbled on Thursday morning.

"It is sad to think of our village, and we are also panicked seeing the continuous eruptions. Since last night and this morning, we're still worried," said evacuee Antonius Puka, 56.

Laki-Laki, which means "man" in Indonesian, is twinned with a calmer volcano named after the Indonesian word for "woman".

Indonesia, a vast archipelago nation, experiences frequent seismic and volcanic activity due to its position on the Pacific "Ring of Fire".