A magnitude 5.5 earthquake struck off the southwestern Turkish coastal town Datça early Sunday, the country's disaster authority announced. It was the biggest among 131 earthquakes reported near the same area in the past 12 hours.

The Disaster and Emergency Management Authority (AFAD) said the 5.5 magnitude quake struck off the coast near Muğla at 7:31 a.m. local time (4:31 a.m. GMT). It occurred at a depth of 14.85 kilometers (9.2 miles) below the surface, it added. Its distance to the coast was around 41 kilometers (25.5 miles). Turkish Deputy Interior Minister İsmail Çataklı said on Twitter there have been no reports of damage or casualties so far.

In the meantime, the Institute of Geodynamics in Athens announced the magnitude of the earthquake as 5.4 and its epicenter as Nisyros, a small Greek island west of Rhodes, some 117 kilometers from Datça. The quake's epicenter was 23 kilometers (14.3 miles) southwest of Nisyros, a small island with about 1,000 inhabitants and an active volcano. The tremor occurred at 7:31 a.m. local time (4:31 a.m. GMT) at a depth of 15.6 kilometers (9.7 miles), the institute reported.

Turkey, a country sitting on multiple active fault lines, had tightened inspections of buildings and implemented regulations to boost the safety of new buildings after the notorious 1999 earthquake that killed thousands in Istanbul and neighboring provinces.