London said the 24 highly-trained specialist firearms officers and the Royal Fleet Auxiliary vessel were sent after a "major surge" in crime which has seen 15 fatal shootings since early September.

An American tourist, who worked as a civil rights activist in the United States, was among the latest victims at the weekend after gunmen opened fire on a vehicle.

The spike in violence is believed to be linked to the arrival of organised criminal gangs from elsewhere in the Caribbean, according to the Foreign, Commonwealth and Development Office (FCDO) in London.

The UK, which is responsible for the safety and security of the islands' 50,000 residents, said the detachment of police officers from the neighbouring Bahamas were already on active duty after arriving on Friday.

The FCDO added discussions were under way with other nearby states on additional support.

"In parallel, the UK is providing a package of longer-term support to build local capacity on areas including intelligence gathering, firearms training and border control," it noted.

Meanwhile, the navy has deployed a tanker from the Royal Fleet Auxiliary -- its uniformed civilian branch, staffed by UK merchant sailors -- which will be used as a "platform for operations".

It has on board a Wildcat helicopter, which offers a surveillance capability and can support security operations.

The US has also agreed to provide a package of maritime surveillance support throughout October, including a fixed-wing aircraft and a Blackhawk helicopter, the FCDO said.

"We had to act following the terrible violence we've seen in the Turks and Caicos Islands these past few weeks," Foreign Secretary James Cleverly said in a statement.

He added the UK-appointed governor, British diplomat Nigel Dakin, and democratically elected premier, Washington Misick, were "also working tirelessly to protect communities".

"Together, we will ensure that violent crime is stamped out in the Turks and Caicos Islands in the long term."