ISTANBUL -- A 5.8 magnitude earthquake in Istanbul slightly injured eight people Thursday and sent school children and residents into the streets of Turkey's commercial and cultural hub.

The Disaster and Emergency Management Authority said the earthquake struck in the Sea of Marmara at 1:59 p.m. (1059 GMT) at 7 kilometers (4.4 miles) deep and was felt throughout the western Marmara region.

President Recep Tayyip Erdogan said eight people were injured and had received treatment. "Apart from small damage, we have not received any reports so far that would pain our hearts," he said.

Health Minister Fahrettin Koca on Twitter confirmed there were no deaths.

News footage showed a collapsed minaret in the city's western Avcilar district. The emergency agency said one building tilted, two showed damage and cracks were found in others. Turkish media showed children being evacuated from schools and city residents waiting outside their homes. Schools were cancelled for the day.

The U.S. Geological Survey assessed the quake's magnitude at 5.7. The Kandilli Observatory and Earthquake Research Institute recorded several aftershocks, with the highest at 4.4 magnitude.

Turkey is crossed by fault lines and prone to earthquakes. Experts have long warned that a major earthquake is expected to hit Istanbul, Turkey's most populous city with more than 15 million residents. A 4.6 magnitude earthquake hit the city on Tuesday.

In 1999, a 7.4 magnitude earthquake in western Turkey killed more than 17,000 people.