CHENGDU, May 12 (Xinhua) -- About 3,000 to 5,000 people are feared dead after a major earthquake in the Beichuan County in northeastern Sichuan, and about 10,000 people were injured, the Sichuan provincial disaster relief headquarters said Monday evening.

    Xinhua has no other sources to confirm the casualties there.

    The officials said 80 percent of the buildings collapsed in the Beichuan Qiang Autonomous County after the quake, northeast of provincial capital Chengdu.

    Casualties are being reported from across the Sichuan Province, after an earthquake measuring 7.8 on the Richter scale shook the area at 2:28 p.m. Monday. The epicenter of the quake was in Wenchuan County, about 159 kilometers northwest of Chengdu.

    The Sichuan Provincial Seismological Bureau said about 313 after-shocks measuring up to six degrees on the Richter Scale have been recorded by 5:28 p.m. Monday in the province.

    Local authorities said they are struggling to reach Wenchuan, believed to be the worst hit area in the quake. Army stationed in the local areas have sent in helicopters to the quake-hit areas for rescue work.

    Chinese Premier Wen Jiabao arrived in Chengdu Monday afternoon by plane and was on the way to the quake-hit county of Wenchuan.

    Wen called the quake a "major geological disaster", and called for calm, confidence, efficiency, and strong leadership in the face of the disaster.