A 7.1-magnitude earthquake hit northwest China's Qinghai Province early on Wednesday, the China Earthquake Networks Center said.

Residents and witnesses near the epicenter said there have been casualties and house collapses.

The quake struck the Yushu County, Tibetan Autonomous Prefecture of Yushu at 7:49 a.m. with a depth of about 33 km. The epicenter is calculated to be 33.1 north and 96.7 east, the China Earthquake Networks Center reported.

Earlier on 5:39 a.m., a 4.7-magnitude jolted the county with a depth of about 6 km, the center reported.