A Spanish ship has illegally entered Gibraltar's territorial waters, the government has said.
The news comes amid increasing tensions between the UK and Spain over the sovereignty of the British Overseas Territory.
Those tensions came to a head over the weekend when the former minister Michael Howard suggested that Theresa May could go to war to protect the strategic enclave, a threat the Prime Minister did not immediately deny. Her spokesperson has since played down those comments.
Spain told Britain to calm down over threats, suggesting the government had lost its composure.
A spokeswoman for the government of Gibraltar told the Press Association: "The ship entered British/Gibraltarian territorial waters. It was met by the Gibraltar Squadron and invited to leave." The spokeswoman couldn't say whether Gibraltar would make a formal protest over the incident.
The status of the waters around Gibraltar continue to be debated. Spain has previously suggested that the UK can claim only the rock and not the water that surrounds it, while Gibraltar itself believes it owns the surrounding sea.
Occasionally that disputed status has led to flare-ups, when Spanish military and tourist vessels have entered into water that is claimed by Gibraltar.
The future of Gibraltar is the first major dispute of the negotiations over Britain's exit from the EU, which began when Article 50 was triggered last week. Tensions flared when Gibraltar featured in a document outlining the plans for those negotiations, which suggested that Spain would be given a veto over any agreements that cover the British territory.
