Rescuers may have killed UK Afghan aid worker: Cameron

British aid worker Linda Norgrove may have been accidentally killed by US forces during a rescue mission in Afghanistan, David Cameron has said.
International forces there originally said the 36-year-old died on Friday when one of her captors detonated a suicide vest.
But the prime minister said new details had come to light suggesting her death may have resulted from a US grenade.
He said he had spoken to her family about the "deeply distressing" news.
Cameron said he was told of the new developments in a phone call from Gen David Petraeus, the top US commander in Afghanistan, on Monday morning.
He said the general told him US forces were deeply dismayed at the outcome and said it was "deeply regrettable" that information published on Saturday about Norgrove was highly likely to have been incorrect.
The BBC's diplomatic correspondent Bridget Kendall said events would raise questions over UK and US relations.
He said he took full responsibility for authorizing the operation to rescue Linda Norgrove, who worked for US aid group. She had been kidnapped on September 26.
At the Downing Street press conference, Cameron defended the rescue mission, saying it had his full support as Norgrove had been in "grave danger".
He said: "The decision to launch this rescue operation was not an easy one. But I am clear that Linda's life was in grave danger from the moment she was taken.
"Those on the ground and in London feared that she was going to be passed up the terrorist chain which would increase further the already high risk that she would be killed."
Cameron said 12 meetings of the government emergencies committee, Cobra, had taken place before Foreign Secretary William Hague and the US agreed the rescue attempt should go ahead. His decision was then approved by the prime minister.
It had been thought that Norgrove had been killed by her abductors just as US forces reached the compound in which she was being held in Afghanistan.
But at the start of the conference, Cameron said it had since emerged that she may have died as a result of a US grenade being detonated during the rescue.
Cameron said it had not yet been confirmed that was the case but a full US/UK investigation was being launched.
"We must get to the bottom of what happened, first of all so the family gets this information and knows exactly how their wonderful daughter died," he said.
Cameron told the conference: "My thoughts and the thoughts of the whole country are with them, as they come to terms with the death of their daughter and this deeply distressing development.
"Linda's death is a tragedy for her family and those who worked alongside her in Afghanistan. She was a dedicated professional doing a job she loved in a country she loved."
Speaking from the Isle of Lewis, Norgrove said: "We are not saying anything to the press at the moment. We might issue a statement in another day or two, we're not certain, but now we are not saying anything."
Cameron added that Norgrove, who was seized in the province of Kunar on 26 September, was being held in remote and high mountains, making the rescue operation very difficult.
Three local staff were also kidnapped alongside Norgrove when the two cars they were travelling in were ambushed. The staff were released unharmed last week.
The Briton, who was employed by US aid group DAI, is believed to have been taken by her captors from village to village as British, Afghan and other intelligence agencies searched the remote area.
It was reported that tribal elders negotiating her release asked Nato not to intervene so they had more time.
Meanwhile, US General David Petraeus on Monday ordered an investigation into the death of a British hostage, saying it was not possible to determine conclusively the cause of her death following an attempted rescue.