More than 10 police officers were injured in clashes with protesters on Saturday in Savoy, on the sidelines of a protest against the opening of a tunnel that will serve a high-speed rail line in the Alps.

About 2,000 protesters gathered in the Morien Valley to express their opposition to the opening of a tunnel to serve the rail link between Lyon and Turin, Italy. Among them were nearly 300 hooded men who attacked the police with stones. Security forces responded with tear gas, and one protester was reported injured, according to prefect Francois Ravier.

French Interior Minister Gérald Darmandin announced the number of injured police officers in a tweet.

Around 400 items, including knives and hammers, were found and seized during border controls, while 96 “people familiar with the security services” were sent back to Italy, according to a statement.