Athens - A strong earthquake measuring 6.6 on the Richter scale shook north-eastern Greece early Tuesday, but there were no reports of injuries or damage.

The underwater quake took place at 5:06 am (0306 GMT) and had an epicentre north-east of Athens near Halkida and the island of Evia.

Two smaller earthquakes took place a few minutes later.

The earthquake startled people in Athens. (dpa)