Indonesia's Mount Merapi unleashed its ball of fire, turning the sky red, spitting out a river of molten lava on Thursday, forcing over 250 people to flee their homes, authorities said. 

The volcano erupted multiple times overnight, spewing gas, volcanic ash, and rocks that flowed over five kilometers down its slopes, the head of Indonesia's National Disaster Management and Mitigation Agency said. 

"Due to the avalanches of hot clouds and ash, 253 people took shelter," Abdul Muhari said in a statement. 

Residents have been told to steer clear of an area spanning a seven-kilometer radius surrounding Merapi's crater over warnings of lava and airborne volcanic material, Muhari added. 

The sky was covered with hot clouds and smoke from the eruption, in Java islands, near Indonesia's cultural capital Yogyakarta.

Mount Merapi is on its second-highest alert level since November 2020 after showing renewed activity.

Its last eruption in 2010 killed more than 300 people and forced 280,000 residents to evacuate from surrounding areas.