A strong earthquake, measuring 6.6 on the Richter scale, has hit the Indonesian island of Sumatra but there are no immediate reports of casualties or damage.

The quake was centred 60km southeast of the North Sumatra provincial capital, Medan, at a depth of 200km.Indonesia was the nation worst hit by the earthquake-triggered Asian tsunami two years ago, with 168,000 people killed in Aceh province in the north of Sumatra.A quake on the south coast of the main island of Java also killed more than 600 people in July.