A tiny British island territory is embroiled in a diplomatic row with the United States after refusing to release five Americans accused of carrying ammunition in their holiday luggage, The Telegraph can reveal.

The Turks and Caicos Islands, a Caribbean archipelago governed as a British Overseas Territory, has arrested the tourists on suspicion of illegally transporting ammunition.

Under the islands’ strict anti-firearms laws, passed in 2022 to deter gang crime, all five now face 12 years in prison if they are convicted.

The tourists all live in states where guns can be used legally, and claim the rounds were inadvertently left in their bags.

The Telegraph can reveal that the US government is protesting the tourists’ detention, arguing that more than a decade behind bars is too harsh a punishment for their alleged crimes.

A delegation of congressmen and US government officials was dispatched on Monday to negotiate with the territory’s officials in an attempt to secure their release.

However, in a statement released on Monday night, the governor’s office said it would not intervene in the cases, which it described as “ongoing”, due to the “constitutional separation of the executive and legal branches”.

It added that while a judge may exercise discretion in the tourists’ cases, their alleged crime carries a mandatory prison sentence of 12 years in prison, plus a fine.

US officials furious over treatment of ‘well-intentioned Americans’

The decision has provoked fury from US officials and the congressmen, who threatened “additional actions” against the British-owned territory if it is not reversed.

The US congressional delegation was led by Markwayne Mullin, a Republican senator from Oklahoma, and included an official from the US State Department, the Pennsylvania senator John Fetterman and three members of the US House of Representatives.

They met with Dileeni Daniel-Selvaratnam, a former civil servant and the islands’ British-appointed governor, and a representative from the Foreign Office.

Although the Turks and Caicos Islands are part of the UK’s sovereign territory, they have an independent legal system and can pass laws without Westminster approval.

Mr Mullin told The Telegraph he hoped to find “common ground” with the islands over the imprisoned Americans but was “not able to find a path forward”.

“At this point, well-intentioned American citizens are facing a dozen years in prison all for unknowingly having one or two bullets in their luggage,” he said.

“The unintended consequences of [Turks and Caicos’s] law have been at the expense of well-intentioned American tourists, including a grandmother, who had no intention of breaking the law.

“We will stay at the table through this process until the issue is resolved. With two hearings on the docket this week, I remain hopeful.

“Should they receive a prison sentence, we will need to consider additional actions to safeguard American citizens.”

Arrested man was visiting for a 40th birthday party

One of the men, Ryan Watson, went to the islands with his wife and other couples for a joint 40th birthday celebration, his sister said on a GoFundMe page she set up to raise money for his legal bills.

As Mr Watson was leaving the territory, airport security found four rounds of ammunition in a duffel bag he had previously used for a hunting trip. His case is set to be heard within days.

A second tourist, Sharitta Shanise Grier, was visiting the islands for a Mothers’ Day trip with her daughter when she was arrested on Thursday.

The others have been identified as Michael Evans, of Texas, Bryan Hagerich, of Pennsylvania, and Tyler Wenrich of Virginia.

Turks and Caicos has a population of less than 50,000 people, and is primarily known as an offshore tax haven and holiday destination for American tourists.

At least one tourism boss is understood to have complained to the islands’ government over the potential impact on revenue if the Americans are not released.

The National Rifle Association (NRA) and three US governors have also released statements in recent days, calling on Turks and Caicos to release the Americans.

The Foreign Office declined to comment.