Thousands of protesters on Sunday fought with Italian police while protesting construction of a high-speed rail linking Italy to France.

Local media said about 50 police officers were injured in the clashes with demonstrators in the Val di Susa area near Turin.

On the Italian side, construction was brought to a standstill by protests before and after the Turin Winter Olympics in 2006. But protests resumed this week after a new construction site opened in Chiomonte.

Many residents around border between Italy and France believe a high-speed rail line would destroy the area, and they oppose the drilling of a tunnel which they claim could release potentially harmful materials.

On last Sunday, 30 people were hurt when police clashed with demonstrators as construction workers were to start work on boring a tunnel in the Susa Valley near Turin.

The leader of the "No Tav" (No to the high-speed train) movement, Alberto Perino, said demonstrators in Sunday's march would have "bare hands and clean hands, against those whose hands are neither bare nor clean", according to local media.

Twenty-three local mayors are against the project, signed by Italy and France in 2001, to build the high-speed link, which would slice three hours off the current seven-hour journey time between Paris and Milan.

Work on the main 58-kilometer (36-mile) tunnel, of which 12 kilometers are in Italy, is scheduled to begin in 2013. It is expected to go into service around 2023.