An explosion occurred on Tuesday afternoon on a lottery market in southwest China's Guizhou Province, injuring 33.

The explosion happened at around 13:00 p.m. Tuesday at a lottery market in Dayingpo of provincial capital city of Guiyang, and injured 33 people. Four seriously wounded are being treated in hospital by the press time.

The accident was caused by a powerful explosion device put under the awarding platform of the market, which split many steel bars into pieces, sources said.

The police has launched investigation into the case.

Source: Xinhua