Norgrove 'may have been killed by US grenade'

British aid worker Linda Norgrove may have been killed by a grenade thrown by US troops trying to rescue her from Taliban kidnappers in Afghanistan, British Prime Minister David Cameron said today.

Mr Cameron announced that a full US/UK investigation is being launched into the circumstances surrounding the 36-year-old's death on Friday.

It had initially been reported that Ms Norgrove died after her rebel captors detonated a bomb vest as American troops attempted to rescue her.

Originally from Sutherland in the Scottish Highlands, Ms Norgrove was seized by militants in Kunar province on September 26.

Three Afghan nationals also taken by the insurgents were later released, but Ms Norgrove continued to be held amid growing concern.

Speaking at a press conference at 10 Downing Street, Mr Cameron said it was not yet certain that Ms Norgrove's death was caused by allied forces.

US commander General David Petraeus informed Downing Street this morning that a review of the rescue operation had uncovered new information suggesting that a grenade detonated by taskforce members may have been to blame.

Mr Cameron informed Ms Norgrove's family of the "deeply distressing development" before making his announcement at a scheduled press conference which was delayed by almost an hour this morning.

He said the decision to mount a rescue operation was made by British Foreign Secretary William Hague "after careful consideration" and had his full support as Prime Minister.

Ms Norgrove's life was in "grave danger" from the moment she was seized, and there were fears that she might be passed up the terrorist chain and put at greater peril if she was not rescued.

"I am clear that the best chance of saving Linda's life was to go ahead, recognising that any operation was fraught with risk for all those involved and success was by no means guaranteed," said Mr Cameron.

Cameron said the initial reports of how the hostage died were "deeply regrettable" but were made in good faith on the basis of the information available.

"None of us can understand just how painful this must be for Linda's family," he said.

"Also it is deeply regrettable, particularly for them, that the information published on Saturday is highly likely to have been incorrect.

"The statements were made in good faith and on the basis of the information that we received.

"I want to assure Mr and Mrs Norgrove that I will do everything I possibly can to establish the full facts and give them certainty about how their daughter died."

Mr Cameron said General Petraeus had treated the hostage "as if she was a US citizen" and that "he and the US forces did everything in their power to bring Linda home safely".

"The US forces placed their own lives in danger. General Petraeus has told me they are deeply dismayed at the outcome. I want to thank them for their courage," he said.

British Foreign Secretary William Hague will make a full statement to MPs in the Commons this afternoon.