UPDATE – 3.00pm – The Tsnami alert has now been officially cancelled. The Pacific Tsunami Warning Center (PWTC) has released a statement that says “the threat has diminished or is over for most areas”.

Indonesia’s disaster mitigation agency sprung into alert mode an aftershock measuring 6.5 on the Richter scale was felt in capital Banda Aceh, where a rescue team has just been dispatched.

The U.S. Geological Survey said the earthquake occurred 33 kilometres beneath the ocean floor and around 495 kilometres out from Aceh, near where the 2004 Indonesian tsunami (pictured above) occured.

“The quake was felt very strongly. Electricity is down, there’s traffic jams to access higher ground. Sirens and Koran recitals from mosques are everywhere,” said disaster mitigation agency spokesman Sutopo Purwo Nugroho.

Twitter users said the tremors were felt in Singapore, Thailand, Malaysia and India.

Because of its close proximity to a series of fault lines, Indonesia is prone to earthquakes and tsunamis.

In December 2004, a 9.1-magnitude quake in Indonesia triggered one of the most destructive tsunamis in history, killing 230,000 people.

Photo: Getty