Two Chinese citizens have been killed and one injured in a suspected bomb attack in Laos, China's official Xinhua News Agency reported Monday.

The bombing took place about 8:00 a.m. on Sunday in the remote mountainous province of Xaysomboun when the victims, one of whom was employed by a Chinese mining company, were riding in a vehicle, Xinhua reported.

Chinese diplomats have visited the survivor, identified by the surname Zhou, and have requested a swift investigation into the incident, Xinhua said.

China is a major investor in Laos' rich abundance of minerals and other natural materials and shares its one-party form of authoritarian communist government. A special Chinese presidential envoy, Song Tao, is due to visit the country this week, Xinhua said.

Located in central Laos, Xaysomboun was closed to tourists for decades after once serving as the center of a secret U.S.-backed guerrilla-led war against communist forces.