Greek authorities have warned of an increase in seismic activity around the Aegean tourist island of Santorini, advising people to avoid four ports, empty their pools, refrain from gathering in indoor spaces and shut schools on Monday.

The strongest earthquake recorded was magnitude 4.6 at 3:55 p.m. Sunday, at a depth of 14 kilometers (9 miles), the Athens Geodynamic Institute said.

Greece ’s top tourist island has been forced to shut its schools on Monday due to an increase in seismic activity in the area. Authorities have advised people on the Aegean island of Santorini to also avoid two small ports and refrain from gathering in indoor spaces after increased tremors in the area over recent days.

Greek authorities have advised people on the Aegean island of Santorini to shut schools on Monday, avoid two small ports and refrain from gathering in indoor spaces after increased seismic activity in the area over recent days.

The Foreign Office has issued a warning for British travellers hoping to visit one of Greece’s most popular islands. Schools on Santorini have been forced to close down following an increase in seismic activity in the area.