Four Chinese technicians died in an explosion Tuesday while building a hydroelectric plant in southern Ecuador.

The victims were explosives experts working on the Chinese-financed Sopladora plant, a project leader told AFP Wednesday.

"These people were working on the expansion of a loading pit at the time of the explosion, whose cause is still being investigated," Tito Torres, manager of state-run Hidropaute, the company in charge of construction, said Wednesday.

The project, which began in 2011, is part of a network of eight hydroelectric plants that are being constructed.

Oil-producing Ecuador hopes that the project will enable it to stop importing electric power and become an exporter of clean energy.

The Sopladora plant, located between Azuay and Morona Santiago provinces, is valued at $678 million and employs about 2,200 workers, of whom 400 are Chinese, Torres said.

Sopladora, with a capacity of 487 megawatts, is expected to be operational in 2015.