Indonesia ? Tens of thousands of people were ordered by police – some at gunpoint – to leave their homes on the slopes of one of Indonesia’s deadliest volcanoes Friday after a series of underground tremors heightened fears of an imminent eruption.

Scientists raised the alert at Mount Kelud to the highest level earlier this week, pointing to sharply rising temperatures in the lake of its crater and violent rumbling beneath.

There was an hourlong spike in the underground tremors and temperature on Friday when gas or magma tried to break through the crater lake, said Surono, a government volcanologist who goes by only one name. The activity then subsided.

Authorities ordered 116,000 people living along the volcano’s fertile slopes to leave their homes Friday, but many have refused.

Police forced many people to leave at gunpoint, calling the situation “critical.”