ANKARA, Turkey - An earthquake with a preliminary magnitude of 5.5 shook the Turkish capital early Thursday, rattling furniture and rousing residents from their sleep, authorities said. There were no immediate reports of injuries.

The epicenter of the quake, which hit at 1:47 a.m., was in the town of Bala, some 50 miles south of Ankara, said Dogan Kalafat, an official from the Istanbul-based Kandilli observatory.

A magnitude 5.7 temblor had also rocked Bala a week ago, damaging around 20 houses and bringing down the minaret of a mosque in Saripinar, a nearby abandoned village.

Gov. Kemal Onal said there were no reported casualties from Thursday's quake, but added that officials were still trying to assess the situation in the region's villages.

Earthquakes are frequent in Turkey, much of which lies atop the active North Anatolian fault, though they are rare in the capital.

Two devastating earthquakes killed about 18,000 people in northwestern Turkey in 1999. In 2003, a school dormitory collapsed following a 6.4-magnitude earthquake in Bingol, in southeast Turkey, killing 83 children.