So far, there have been no reports of damage or casualties.
The quake occurred some 9 km north of Pernik, which is 25 km west of Sofia, around 3 a.m. (0000 GMT) with its epicenter at a depth of 9.10 km.
Xinhua journalists in Sofia said that the quake was strongly felt in the city, and the Internet links had been cut off by the tremor.
People were waken by the quake, with many of them seen running out of their houses to avoid injuries.
While moderate quakes are not rare in the European country, Bulgaria has not been struck by a strong earthquake for many years.
(C003)
Editor: Ella Syafputri
Copyright © ANTARA 2012
