The final stage of the Vuelta a Espana was abandoned after pro-Palestinian protesters entered part of the course in the centre of Madrid.
Protesters knocked down barriers and occupied the road at several points on the course including Gran Via, where cyclists were due to pass multiple times.
More than 1,000 police officers had been deployed on to the streets of the Spanish capital, with demonstrations expected.
Danish cyclist Jonas Vingegaard, who led going into the 21st and final stage, was declared the winner - a first Vuelta title for the two-time Tour de France champion.
Tradition dictates rivals do not seek to overhaul the leader on the last day of a Grand Tour. Britain's Tom Pidcock finished third, behind Joao Almeida.
The riders were stopped with around 60km remaining as they arrived at the finishing circuit in Madrid before the stage was abandoned.
There have been various protests against the Israel-Premier Tech team throughout this year's Vuelta, forcing some stages to be shortened.
Riders had expressed concerns for their safety due to the protests, which led Israel-Premier Tech to compete in modified jerseys without their team name.
Vingegaard expressed disappointment over the race's abandonment, stating, It's a pity that such a moment of eternity was taken from us. Everyone has the right to protest, but not in a way that influences or endangers our race.
Clashes continued following the race's abandonment, with protesters throwing objects at police.
The protests align with unrest in the region, following the Israeli military's campaign in Gaza after the October 7 attacks that left many dead.
Spanish Prime Minister Pedro Sanchez expressed admiration for the protesters, a move that drew criticism from Madrid's mayor, who accused Sanchez of inciting violence.
Israel's foreign minister labeled Sanchez's remarks disgraceful, suggesting they encouraged protests that disrupted the cycling race.
This incident underscores the occasional convergence of political activism and sporting events, raising questions about the safety of athletes amid political turmoil.
