A pro-migrant activist group has called off an unauthorized protest after Italian border police detained three demonstrators trying to cross from France armed with clubs, knives, a hatchet, a wrench and hoods.

Police said one Italian and two French citizens were being held Sunday.

Tensions along the border have escalated in recent days after dozens of migrants crossed into France by plunging into the sea, evading border controls.

The No Borders activist group said it called off the protest, aimed at pressing for open borders, to avoid provocations. Fearing clashes, authorities had prevented other demonstrators from arriving from elsewhere in Italy.

The 140 migrants who crossed into France were returned to the border town of Ventimiglia, where many arrive after being rescued at sea, hoping to reach northern Europe.