French police pushed back hundreds of Catalan pro-independence activists to the Spanish side of the border on Tuesday after they blocked a busy crossing between the two countries.

Gendarmes moved in during the early morning to evict protesters gathered around La Jonquera crossing as the Catalan police force, the Mossos, started removing vehicles and demonstrators on their side.

People were seen crying after scuffles with the police led to the use of teargas and pepper spray.

The protest on the AP-7 highway near the Spanish city of Girona was planned by a secretive organization Tsunami Democratic and was due to last for three days.

"This mobilization is a cry to the international community so that it makes the Spanish state understand that the only possible path is to sit down and talk," the group said in a message to its followers on encrypted messaging service Telegram.

A second separatist group, CDR, also urged its followers to gather at La Jonquera.

Traffic was cut off in both directions of the road when up to 2,000 activists started gathering at the border on Monday.

They brought food, water, cooking utensils, foldable tables and gas cylinders.

Some of them had their faces covered and held up banners reading "Everyone to La Jonquera" in Catalan.

Demonstrators even started setting up a stage and speakers, ignoring police warnings of forcible eviction if they failed to voluntarily disperse from the site.

The incident came a day after Spain's general election, in which Prime Minister Pedro Sanchez's Socialist party emerged as the leading group in exit polls, albeit slightly weakened. Vox, the far-right party was third.

Mass protests have erupted across the Spanish province of Catalonia after nine separatist leaders were handed long prison sentences over a failed independence bid in 2017.

Road and rail links between Spain and France have been disrupted frequently since then.