A total of 13 people were killed and 12 injured in a tunnel collapse at a Chinese hydroelectric power station under construction in the Ecuadoran Amazon.

Three Chinese and 10 Ecuadorans died in the incident, Ecuadoran President Rafael Correa said on Twitter.

Ecuador's public radio reported that the fatalities occurred in the engine room at the Coca Codo Sinclair hydroelectric station.

"We're evaluating what has happened. It's a problem we're having in the pressurized piping," Dennis Salgado, the project's lead control technician, told AFP.

The Chinese-funded plant employs 7,000 workers -- 20 percent of whom are Chinese -- along the border of the Amazonian Napo and Sucumbios states.

The injured were being treated at a hospital in the town of El Chaco, according to the radio.

Coca Codo Sinclair, constructed by the Chinese firm Sinohydro, cost some $2.2 billion and is scheduled to begin operation in February 2016. It is expected to generate 36 percent of the energy currently consumed in Ecuador.

The plant is part of a network of eight hydroelectric stations under construction in the oil-rich country, which aims to stop importing electricity and become an exporter of clean energy.