Spanish Civil Guard officers break through a door at a polling station for the banned independence referendum where Catalan President Carles Puigdemont was supposed to vote in Sant Julia de Ramis, Spain October 1, 2017. REUTERS/Juan Medina

MANCHESTER, England (Reuters) - Gibraltar is very concerned by violence in Catalonia after Spanish riot police burst into polling stations and seized ballot papers to prevent a banned referendum on a split from Spain, the chief minister of “the Rock” said.

Police hit people with batons, fired rubber bullets into crowds and forcibly removed would-be voters from polling stations in actions that were condemned internationally but were described by the government as “proportionate”.

The referendum, declared illegal by Spain’s central government, has thrown the country into its worst constitutional crisis in decades and deepened a centuries-old rift between Madrid and Barcelona.

Catalan officials said over 460 people had been injured in the police crackdown and the Spanish Interior Ministry said 12 police had been hurt.

“I am very concerned to see violence in the streets of our neighbouring nation,” Chief Minister Fabian Picardo told Reuters in an interview at the Conservative Party conference in the northern English city of Manchester.

Gibraltar, a tiny British enclave on Spain’s southern tip, is dubbed “the Rock” because of its famous cliff-faced mountain. Spain claims sovereignty over the territory it ceded to Britain in 1713.

Spain’s Foreign Minister Alfonso Dastis last month said Gibraltar was an anachronistic colony that had no place in the modern world.

“The claim by Spain to the land that I call my home is anachronistic and remnant of a bygone era,” Picardo said. “But anyone who visits Gibraltar realizes it is far from anachronistic - it is modern, it is digital, it is thrusting and it is prosperous.”

Residents of the territory voted overwhelmingly to remain part of the EU in last year’s Brexit referendum. Gibraltar wants London to negotiate a “special status” with the EU for it after the British exit.