(Madrid) Four Catalan separatists were arrested on Saturday, suspected of having tried to sabotage the Vuelta, the Tour of Spain cycling, when they planned to pour motor oil on part of the road taken by the runners.

The group were arrested in the woods near Suria, in the north-eastern region of Catalonia as they were about to spill 400 liters of a “liquid similar to motor oil”, contained in two drums, on the road, the national police said in a statement on Tuesday.

The suspects are supporters of Catalan independence, according to far-left separatist group Alerta Solidaria on X (formerly Twitter), which fiercely opposed the Vuelta’s passage through the region, calling it “colonialist”.

The drums and the pipe that connected them to the highway “were hidden in vegetation, making them difficult to detect,” the statement added. The targeted section was taken on Monday by the third stage of the Vuelta, a 158.5 kilometer journey linking Suria to Arinsal in Andorra.

The four men were indicted for membership of a criminal group, disturbing public order and crimes against the environment. They left free after appearing in court but were prohibited from approaching the roads taken by the route of the cycle race, their lawyer Eva Pous told the Catalan media.

Along with the Tour de France and the Giro d’Italia, the Vuelta is one of the prestigious Grand Tours of cycling. This is the 78e edition of the race, which will end in Madrid on September 17 after 21 stages and 3153.8 kilometers.