NEW: Deaths caused by smoke inhalation and collapsing wall
Flights at area airports are canceled because of the ash
Indonesian government raises its eruption alert to its highest level
Mount Kelud last erupted in 2007; a 1990 eruption was deadly
Some things returned to normal in Indonesia on Saturday after a volcano erupted two days before, but tens of thousands of evacuees were yet to return to their homes.
Of those who died, two perished from smoke inhalation, while the third was hit by a collapsing wall. A fourth person died when ash caused a roof to collapse.
Mount Kelud, located in the eastern part of the main island of Java, had been spewing ash high into the air, as a smoke plume has risen from out of its crater into the sky.
The government raised its eruption alert to its highest level overnight, and authorities have ordered an evacuation of all residents in a 10-kilometer (6.2 miles) radius of the volcano in eastern Java.
At the height of the crisis Friday, 100,000 people evacuated.
Seven airports closed due to volcanic ash, which filled the skies and can lead to jet engine problems.
Lightning was seen striking the volcano’s peak as it spewed debris, according to National Disaster Mitigation Agency spokesman Sutopo Purwo Nugroho.
The nation’s volcanology agency said other smaller eruptions could happen. Authorities urged people to stay outside the 10-kilometer radius.
Pictures from the scene show large black plumes rising over Mount Kelud, raining pebbles and ash on the surrounding area.
The military has been called in to help evacuate people from the area to nearby shelters.
Mount Kelud last erupted in 2007, but it has ramped up activity in the past 10 days.
In 1990, an eruption killed more than 30 people and injured hundreds.
Indonesia is part of the vast “Pacific Ring of Fire,” an area of colliding continental plates where powerful earthquakes and volcanic eruptions often occur.
CNN’s Brian Walker contributed to this report.