Speaking from Brussels, Mitsotakis said authorities were monitoring a "very intense" geological phenomenon over recent days, adding: "I want to ask our islanders above all to remain calm."

Known for its spectacular cliffside views and a dormant volcano, Santorini and neighbouring Aegean Sea islands have been hit by hundreds of tremors since last week, the largest with a magnitude of 4.9.

The activity has prompted authorities to send rescue units to the area and close schools, and some areas have been declared off-limits because of rockslide risks.

Many among the population of over 15,000 spent the night outdoors, while others are leaving the island by sea and air.

Santorini is among Greece's premier travel destinations, with 3.4 million visitors in 2023.