Beijing: Chinese teams have located 50 radioactive sources last week’s earthquake in Sichuan province, a senior official said on Friday.

Fifteen have yet to be recovered, said Vice Environment Minister Wu Xiaoqing.

"Three are buried in rubble and another 12 are in dangerous buildings, which staff cannot go into," he said.

There have been no accidental releases of radiation, he said.

The disaster area is home to China's chief nuclear weapons research lab in Mianyang, as well as several secretive atomic sites.