Local police said on Friday that they will take a zero tolerance approach to crime in the parish of St. James, where Montego Bay is located, and nearby communities that have seen an increase in killings that officials blame on gangs and lottery scams.
The tourists were urged to follow the local advice including restrictions in selected areas, and exercise particular care if travelling at night. "You should exercise caution if you're in the area".
Jamaica Constabulary's force police commissioner, George Quallo, told the Jamaica Information Service 335 murders were recorded in St James Parish in 2017, nearly twice as many as the other parishes.
A auto carrying three men and a child was sprayed with bullets in a drive-by shooting on Tuesday afternoon, a stone's throw from Sangster International Airport.
The statement reads: "Tourists should stay in their resorts and limit travel beyond their respective security perimeters".
The lockdown also allows for detaining suspects beyond normal laws and setting up checkpoints to stop and search vehicles and people.
Those who venture beyond should use transportation arranged by the resort and only use organized tour operators for excursions and travel. Miraculously, the child was unhurt.
The FCO said: "A state of emergency has been declared in St James Parish, which includes Montego Bay".
The UK Government has urged Britons to stay in their hotels while the "major" military operation takes place in St James Parish.
"This is a very worrying time for tourists caught up in this war on crime".
Mr Holness said members of the security forces would be equipped with "extraordinary powers" to deal with the situation.
The UK had a similar message for Brits traveling to the area.
"But what people need to know is this is a developing country with all the associated problems and with the high murder rate unfortunately life is cheap".
The travel warnings came after Jamaica's Prime Minister, Andrew Holness, announced a state of emergency for St. James Parish on Thursday and deployed military to the area amid a rise in violent crime.