Government officials, including Civil Protection Minister Vasilis Kikilias ordered the move after a series of tremors in the sea around Santorini and surrounding islands, the site of one of the largest volcanic eruptions in recorded history.

Dozens of small earthquakes have been recorded, the strongest so far was magnitude 4.6.

On Sunday, quakes of magnitude 4.1 and 4.5 shook the region, according to the Department of Geophysics of the University of Athens.

This was preceded by 11 other earthquakes within a few hours.

Authorities said the quakes are because of tectonic rather than volcanic activity, according to Athens News Agency.

Greek authorities called for citizens to avoid large gatherings in enclosed spaces and stay away from certain built up areas.

Santorini is one of the most popular Greek islands for tourists. It has a population of just 15,500 but welcomed 3.4 million visitors in 2023, raising concerns about the phenomenon of overtourism.