Jakarta, May 26 (IANS): Mount Sinabung in Indonesia's North Sumatra province erupted again on Thursday, spewing a column of ash by up to 2.5 km into the sky, a volcanologist said.

"The seismic activity of the volcano, which has been declared on top alert level, remains high and the potential of further eruption remains," said Hendra Gunawan, head of department of national volcanology agency.

"Mount Sinabung erupted after midnight and this morning. The nearby community must be on alert for hot ashes and cold lava floods," he told Xinhua news agency.

The volcanology agency has declared a 6 km dangerous zone from the crater in the southeast and east of the volcano and 7 km in the south, he said.

Seven farmers were killed while two others suffered serious injuries last week as they entered the dangerous zone, said Sutopo Purwo Nugroho, spokesman of the national disaster management agency.

At least 16 people were killed and thousands were forced to flee their homes after a massive eruption occurred at the volcano in February 2014.

Mount Sinabung is one of Indonesia's 129 active volcanos located on a quake-prone zone called the 'Pacific Ring of Fire'.