Protesters carried banners saying 'No to the TAV' (TGV) rail link

Schools, shops and many businesses in the Susa valley closed to allow local people to take part in the protest.

A motorway and a railway already run through the valley, and residents say the planned line from Turin to the French city of Lyon is unnecessary.

Turin is the site of the Winter Games that will run from February next year.

Unlike earlier protests, the march was peaceful, but Italian Interior Minister Giuseppe Pisanu says the protesters have been infiltrated by anarchists.

Choked

Protesters were marching from the village of Bussoleno to Susa, 8km (five miles) away, for a concert and protest rally.

The action has widespread support among locals in the region, who add that the rail link will cause further damage to the environment.

"The valley is already choked with transport infrastructure, with a motorway, two national highways and a rail line," the head of the Susa Valley community association, Antonio Ferrentino, told AFP.

"No government can ignore it when an entire region protests. We want our say."

The agreement to go ahead with the TGV rail link, which is being built by dual nationality company LTF and involves a 53km tunnel through the Alps, was announced in 2001.

The multi-billion dollar project is expected to open in 2015.

Other protests have resulted in road and rail links between France and Italy being blocked.