The British government says Spanish vessels repeatedly and unlawfully entered its territorial waters belonging to Gibraltar, without permission, on Sunday.
British Foreign Office Minister Hugo Swire said that Spanish vessels and a helicopter entered British waters and airspace illegally. He added that they “repeatedly entered” the territory.
The pursuit was part of a suspected drug-smuggling operation, but it does not give grounds to “illegally” enter British waters, according to the UK.
The Spanish vessels were chasing suspected smugglers in a high-speed inflatable boat as they dumped bales of drugs into the water while trying to escape, according to Gibraltar Chief Minister, Fabian Picardo.
“These repeated incursions into British Gibraltar territorial waters are a clear violation of UK sovereignty by another EU country and we will be raising this as a matter of urgency with the Spanish authorities,” said Swire.
Spain denies wrongdoing and insists that it did not violate British waters.
“The waters are Spanish,” said an official from Spain's Foreign Ministry.
“It was Spanish boats patrolling in Spanish waters to control illegal activities such as tobacco smuggling or illegal fishing,” he added.
Gibraltar is British territory on the southwestern tip of Spain with a population of approximately 30,000, and remains a hot issue of dispute between Spain and Britain.
The Royal Navy uses the territory which was ceded by Britain 300 years ago, as a naval base.