BELGRADE (AP) _ A moderate earthquake shook south-central Serbia this morning near the town of Trstenik, 90 miles south of Belgrade, the Tanjug news agency reported. There were no immediate reports of casualties.

The quake, with a preliminary magnitude of 5.6, damaged some houses weakened earlier during NATO airstrikes, local televesion reported. Several roofs collapsed in the villages of Milutovac and Medvedja, six miles south of Trstenik.