Beneath North Sumatra's luminous sky yesterday, a stunning light display of another kind took place as Mount Sinabung in Karo regency erupted early morning, blasting ash and smoke as high as 4.2km.

The Associated Press reported a local official as saying that at least 19 eruptions followed by lava flows had been recorded by midday yesterday.

The volcano, one of the most active in Indonesia, had erupted repeatedly in recent weeks, displacing more than 7,200 people, of whom many have chosen to stay at evacuation shelters, said Indonesia's disaster management agency BNPB.

While no casualties have been reported, residents were warned to keep away from a danger zone that extends as far as 7km from the peak of the volcano.

BNPB spokesman Sutopo Purwo Nugroho said: "We cannot predict when Mount Sinabung will stop erupting. Volcanic and seismic parameters remain high. Therefore, the potential of follow-up eruptions is still there."

The 2,460m-high Sinabung burst back to life in 2010 after about 400 years of dormancy, and has been quite active since 2013.

In May last year, seven people were killed in one of its eruptions, while 16 were killed in early 2014.