GUANGZHOU - A truckload of explosives went off Monday afternoon, leaving nine people dead and one missing at a quarry of a cement factory in south China's Guangdong province, local authorities said.

The blast occurred at around 2:30 pm when workers were unloading the explosives off the last of three trucks that had been shipping the explosives to the quarry in the city of Yingde, the city government said in a statement released late Monday.

The quarry belongs to the Longshan cement company, which is a subsidiary of the listed Anhui Conch Cement Company -- the largest cement manufacturer in China, according to the statement.

Among the dead were employees of the quarry and workers who transported the explosives from a local private explosives company, said the statement.

The three trucks carried altogether 13 tonnes of explosives and workers had already unloaded six tonnes when the tragedy happened, it said.

The blast also shattered windows in a nearby township, which is separated from the quarry by a river, slightly injuring nine villagers.

The city has set up an emergency response team and asked experts to remove the unexploded explosives.

An investigation into the cause of the blast is underway, said the statement.