British tourists are being warned they should stay inside their resorts in Montego Bay, Jamaica.
The Jamaican government has declared a state of emergency in the St James parish, after a number of "shooting incidents".
The Foreign Office has told British tourists to stay in the confines of their hotels as a "major military operation" takes place.
About 200,000 British tourists holiday in the Montego Bay area every year.
A spokesman for the Foreign Office said: "[Tourists] should follow local advice including restrictions in selected areas, and exercise particular care if travelling at night.
"[They] should stay in their resorts and limit travel beyond their respective security perimeters."
On Thursday the country's prime minister, Andrew Holness, said the state of emergency was "necessary" in order to "restore public safety" in the St James area.
Chief of defence Major General Rocky Meade said: "We ask that you cooperate with the troops.
"The troops have been refreshed in their training of human rights and how to engage with citizens."