A BRITON being held at Guantanamo Bay saw US military interrogators kill two detainees at an American base in Afghanistan, he said in a letter, details of which were being released by his lawyers today.

Moazzam Begg made the claim in an uncensored letter that was released to his legal team by American officials - something his lawyers have described as an "oddity".

Begg is one of four Britons being held at the US prison camp at Guantanamo Bay, Cuba. Prime Minister Tony Blair has personally asked President George W. Bush to free the British detainees.

Begg's handwritten letter, dated July 12, 2004, described mistreatment he suffered while in detention at the US military base in Bagram, Afghanistan, according to BBC radio, which said it had obtained a copy of the letter.

"During several interviews, particularly though unexclusively in Afghanistan, I was subjected to pernicious threats of torture, actual vindictive torture and death threats amongst other coercively employed interrogation techniques," Begg wrote.