LUDIAN, Yunnan, Aug. 7 -- The death roll rose to 615 four days after a powerful earthquake devastated southwest China's Yunnan Province, local authorities said on Thursday.

Among the reported deaths, 526 were in the worst-hit Ludian County and 76 in Qiaojia County. The quake has also caused one death in Zhaoyang District of Zhaotong City and another 12 deaths in Huize County of Qujing City, the local quake relief headquarters said.

The official tally showed that in addition to the deaths, there were 114 missing and 3,143 people injured in the 6.5-magnitude quake as of 7 p.m. on Thursday.

The earthquake, the strongest to strike Yunnan in 14 years, occurred at 4:30 p.m. Sunday (Beijing Time) with its epicenter in Longtoushan Township, Ludian County in Zhaotong City, affecting over 1.08 million people in the cities of Zhaotong and Qujing.