Gale force winds have battered Greece, forcing authorities to shut down many ferries and schools and causing flight delays as meteorologists warned about the possibility of a cyclone in the Ionian Sea.

Ferries remained in port, severing Greek islands’ connection to the mainland.

The strong winds toppled trees on to power lines in the northern suburbs of Athens, with the fire department saying it received more than 350 calls to remove debris.

Waves cover the coastal road during bad weather at the port of Rafina, east of Athens
Waves cover the coastal road at the port of Rafina, east of Athens (Thanassis Stavrakis/AP)

Authorities in the Saronic municipality near Athens, on the Ionian island of Zakynthos and the Aegean islands of Tinos, Andros and Mykonos ordered schools to remain shut.

On the western island of Kefallonia, schools were evacuated near a wildfire that was being fanned by the strong winds.

Authorities described the decision as a precaution, but said the island’s emergency services were on alert as weather conditions were expected to worsen.

Meteorologists warned of the high probability that a Mediterranean cyclone known as a medicane – which combines the words Mediterranean and hurricane – could form on Friday in the Ionian Sea south west of the Greek mainland.

A man takes a photograph during bad weather at the port of Rafina, east of Athens
A man takes a photograph amid bad weather in Rafina (Thanassis Stavrakis/AP)

The Institute of Geodynamics, meanwhile, said an earthquake with a preliminary magnitude of 5.0 struck off the western coast of southern Greece.

No damage or injuries were immediately reported.

Thursday’s quake had an epicentre beneath the seabed 34 kilometres (21 miles) south west of the town of Pylos, 245 kilometres (152 miles) south west of Athens.

The European-Mediterranean Seismological Centre gave the preliminary magnitude as 5.2.

Greece is in a highly seismically active region and earthquakes are frequent.

The vast majority are small and those causing severe damage or loss of life are rare.