MADRID -- French police detained 18 pro-Catalan independence protesters Tuesday and used pepper spray and batons to push back demonstrators who blocked a major highway border crossing between France and Spain for more than 24 hours.

The police then began towing away vehicles and debris with the aim of reopening the road to traffic.

The police action Tuesday led to some scuffles, and some protesters could be seen crying from the effects of the spray. The regional administration said no one was injured in the operation, which took all morning.

Several hundred protesters remained gathered around La Jonquera crossing, and Catalan regional police from Spain were standing by.

The planned three-day protest started Monday. It was organized by a clandestine activist group called Tsunami Democratic, which has staged many protests, some violent, since a dozen Catalan separatist leaders were convicted last month for their role in a 2017 push to make Catalonia independent from Spain.

The administration for the Pyrenees-Orientales region of southern France said the operation to clear out the protesters was carried out in "close co-operation with Spain."

The A9-AP7 highway connecting Perpignan in France with Barcelona in Spain remained blocked Tuesday afternoon, but French highway operator Vinci said it was working to remove obstacles placed by the protesters and hoped to allow traffic to resume shortly.

The highway is a key thoroughfare for trade and tourism between the countries, and thousands of vehicles have been sent on detours through the Pyrenees to try to cross the border elsewhere. Icy conditions in some spots complicated the journey Tuesday.