Jakarta, Jan 4 (IANS): Mount Sinabung, one of the most active volcanoes in Indonesia, erupted again Saturday, shooting a column of ash hundreds of metres in the sky as the number of evacuees rose, official said.

According to Sutopo Purwo Nugroho, spokesman of national disaster agency, powerful burst of hot ash and gravel erupted from the rumbling volcano, located in Karo district of North Sumatra, at least 30 times since Saturday morning. Hot ash has slid off by up to five km from the crater, pushing the authorities to extend evacuation zone from five to 20 km, Xinhua reported.

"The column of hot ash now is the biggest ever compared with those frequently spewed (since the volcano erupted in September) The hot ash has slid off to the southeast, covering two villages," Nugroho added.

The authorities evacuated all the villagers Friday, adding the total number of displaced people to 20,331 Saturday from 19, 286 on the previous day, Nugroho added.

Besides, the authorities also extended emergency relief period from Jan 5 to 18, he said. "The people are recommended to persistently be cautious and abide the authorities' guidance."

The 2,457-metre Mount Sinabung in Karo district of North Sumatra has rumbled to life since September after being quiet for 400 years. It has erupted on and off since then, but went into overdrive frequently in November and December.

On Dec 31, Mount Sinabung erupted, spewing ash up to 7,000 km in the sky, one of the strongest since September.

Mount Sinabung is among the 129 active volcanoes in the vast archipelago country, which is prone to seismic upheaval, as it is situated in the Ring of Fire encircling the Pacific Ocean.