The action that started at 1130 GMT was carried out by some 20 activists from Derniere Renovation (France) and Ultima Generazione (Italy), two sister organisations that belong to the A22 civil resistance movement, the joint statement said.
It was aimed at putting pressure on the French and Italian governments to act to limit climate change.
“We are blocking the road today to open a new route for tomorrow’s children,” said Luca, 28, from Ultra Generazione.