Thousands of people in Sumatra, Indonesia have fled for higher ground, after rumours that the notorious Krakatoa volcano was about to erupt.
People in the coastal town of Lampung feared the volcano would trigger a huge tsunami.
Krakatoa's eruption in 1883 was so powerful that much of the original volcano disappeared, leaving what is known as Anak (Child of) Krakatoa.
Sumatran residents are already nervous after last year's deadly tsunami.
An underwater earthquake on 26 December triggered a sea surge which left at least 126,000 people on the island dead.
Soon after midnight on Tuesday, Lampung residents began to leave their homes in panic.
It is unclear how the rumour began, but it quickly spread as people ran to tell each other or sent mobile text messages to their friends.
"People were running around shouting 'the water is rising, Anak Krakatau [Krakatoa] is erupting'", local police officer Ayatullah told the Associated Press.
"The panic increased when the mosques started telling people to run to higher ground."
Mosques broadcast verses from the Koran over loudspeakers as people fled.
The situation only calmed at dawn, as the sun rose and people could see that Anak Krakatoa showed no signs of change.
Anak Krakatoa lies off the south of Sumatra, on the same tectonic fault-line that caused last December's earthquake.
When Krakatoa erupted in 1883, the explosion was heard as far away as Australia, and caused a tsunami that killed an estimated 36,000 people.
The volcano sent ash and rock into the atmosphere, which altered the Earth's weather patterns for years afterwards.