The Greek island of Santorini has been rattled by a further earthquake.The latest quake, one of thousands to hit the volcanic island in recent weeks, is the strongest so far with a magnitude of 5.3.Medical staff staged a hospital evacuation drill as scientists said it is unclear whether the weeks of highly unusual seismic activity precede a larger quake.

A state of emergency has been declared in Santorini after the strongest earthquake was recorded in days of near-constant tremors, which have almost emptied the famous Greek tourist haven of visitors and residents.