“The evidence surrounding this incident discloses a gross violation of British sovereignty and, potentially, the most serious and dangerous incident for many years,” said Gibraltar’s Chief Minister Fabian Picardo in a statement.

The incident happened early on Thursday when a small Spanish customs vessel lost power while pursuing suspected tobacco smugglers off Gibraltar, a source from Spain’s tax agency which is in charge of customs told AFP.

After choppy seas pushed their vessel to the shore, the two officers on board were surrounded by a group of people and pelted with rocks, some of them weighing over three kilos (6.5 pounds), the source added.

The officers fired “shots into the water to try to drive away” the people throwing rocks, a tax office source told AFP, speaking on condition he was not identified.

One customs officer suffered a broken nose, the other fractured bones in his face, he added.

Videos circulating on social media appear to show several shots being fired during the incident, although it was not clear who fired them.

‘Reckless and dangerous’

“Should it be confirmed that Spanish officials discharged their weapons in Gibraltar, such action would be a very serious breach of the law,” the Gibraltar government statement said.

It called the incident “reckless and dangerous, especially in an area of dense civilian population, given the proximity of a residential estate in the area”.

The governments of Gibraltar and the United Kingdom consider that the events “will require careful consideration as to the nature and level of diplomatic response,” it added.

Gibraltar police and army officers used metal detectors on Friday to search for bullet casings on the beach, images broadcast on Gibraltar TV showed.

Picardo said Spanish law agencies know they can ask Gibraltar law enforcement to continue a chase into Gibraltar but “it would appear that they did not do so in this case.”

Spain’s foreign ministry “categorically rejected” the terms of the Gibraltar government statement as well as the “claims of alleged British sovereignty over the territory and waters of Gibraltar” which it contained.

Spain’s Budget Minister Maria Jesus Montero said the customs agency would “investigate what happened and will demand the necessary explanations”.

Post-Brexit talks

The incident comes as Madrid and London are locked in talks over Gibraltar’s post-Brexit relationship with the European Union.

The European Commission and Spain sent Britain, in late 2022 a proposal that would keep freedom of movement along the border of the tiny British enclave at Spain’s southern tip.

About 15,000 people, the majority of them Spaniards, commute daily from Spain to jobs in Gibraltar, which has a population of about 34,000.

Gibraltar has long been a source of British-Spanish tensions. Although Spain ceded Gibraltar to Britain in 1713, Madrid has long wanted it back, a thorny dispute that has for decades involved pressure on the
frontier.

Tensions peaked in 1969 when the regime of dictator Francisco Franco closed the border, which did not fully reopen until 1985.