Four people were confirmed dead and at least 100 others were injured in an explosion in southwest China\'s Guizhou Province Tuesday, local authorities said. The blast happened at around 11:30 a.m. in Machangping township of Fuquan City, at least 100 km from the provincial capital Guiyang, said a spokesman with the publicity department of the Fuquan city committee of the Communist Party of China. He said the exact location of the explosion was near a ramp on an interprovincial expressway that links Lanzhou in the northwestern Gansu Province with the southernmost island province of Hainan. The explosion toppled several homes nearby, the spokesman said. He said the exact cause of the explosion remained unclear.