BEIJING (AP) — An explosion at a fireworks factory in southern China has killed 11 people and injured 17 others.

The official Xinhua News Agency says the cause of the blast that took place Friday afternoon in the city of Cenxi in the Guangxi autonomous region is unknown.

A man reached at the Guangxi Work Safety Bureau said Saturday that two executives of the factory have been detained.

He only gave his last name as Chen, which is common among China's bureaucrats when speaking to the press.

Workplace safety is a major problem in China where enforcement of laws is lax with factories themselves usually left to decide whether to follow them.