The British Government should increase the Royal Navy's presence in Gibraltar in response to Spanish incursions into its territorial waters, Chief Minister Fabian Picardo has said.
Mr Picardo said the latest alleged incursion - a Spanish research vessel ignoring requests to leave the territory's waters for 20 hours - was a "security issue that Spain needs to be aware of".
He told BBC Radio 4's Today programme that he was "in favour of anything that has a positive deterrent effect" but that "diplomatic aspects must be equally important".
More top news
After a frosty start, southeastern areas will be dry with increasing amounts of sunshine developing. It will remain cold throughout the day.
Higher food and petrol prices are expected to send inflation to its highest level in 28 months when official figures are released later.
The Prime Minister will detail her 12-point plan on negotiating Britain's exit from the European Union during a speech on Tuesday.