Tensions flared-up between the British and Spanish navies on Sunday after a Spanish warship ordered ships to move from UK-controlled waters near Gibraltar.
In audio of the incident obtained by the Gibraltar Chronicle, the crew aboard the Spanish ship was heard ordering anchored boats to "leave Spanish territorial waters."
The Gibraltar Port Authority later told the boats to "stay in position," while the UK's Royal Navy was deployed.
"After being challenged by the Royal Navy, the Spanish warship sailed slowly along the Gibraltar coast with its weapons uncovered and manned," a statement from the Gibraltar government said.
An investigation was launched after the incident in order to ensure "appropriate action" was taken, the statement added.
A Gibraltar government spokesperson said the altercation was evidence of the "foolish games" from the warship.
"It seems there are still some in the Spanish navy who think they can flout international law," the spokesperson said.
"This probably accounts for the state of extremism of some parts of the Spanish political spectrum these days."
A spokesman for UK Prime Minister Theresa May said there was no incursion by the Spanish navy, according to Reuters.
"There was no incursion on this occasion. We are certain of our sovereignty over the whole of Gibraltar, including British-Gibraltar territory waters, and any incursions are a violation of sovereignty, but not a threat to it ," the spokesman said.
Euronews has reached out to the Spanish navy for comment.