Kayakers from across Europe took to Bosnia's Vrbas river on Monday to protest against a boom in dam construction across the western Balkans that campaigners say threaten to cause irreparable environmental damage.

The kayakers joined activists and local people who have been campaigning for years against plans to build two new hydroelectric power plants on the Vrbas river.

The two facilities are part of a planned network of nearly 3,000 plants foreseen across the western Balkans, a region known as the 'blue heart' of Europe for its pristine rivers. About a third of them would be located in protected areas, the campaign groups RiverWatch and EuroNatur said in a study.