ISTANBUL — A powerful earthquake shook northwestern Turkey Sunday, causing people to flee their homes, emergency services said. No casualties were immediately reported.

The magnitude 5.4 quake was centered in the town of Simav in Kutahya province at a depth of 8 kilometers (5 miles), emergency agency AFAD said. The quake struck at 12:59 p.m. (0959 GMT) and was followed by a magnitude 4.0 aftershock. It was also felt in Istanbul, Turkey’s largest city some 100 kilometers (62 miles) to the north, according to media reports.

TV footage showed people in Kutahya gathering in squares and parks following the tremor.

In August, a magnitude 6.1 earthquake struck Sindirgi, in the neighboring province of Balikesir. One person died and dozens were injured. Since then, the region around Balikesir has been hit by smaller shocks.

Turkey sits on top of major fault lines and earthquakes are frequent.

In 2023, a magnitude 7.8 earthquake killed more than 53,000 people in Turkey and destroyed or damaged hundreds of thousands of buildings in 11 southern and southeastern provinces. Another 6,000 people were killed in the northern parts of neighboring Syria.