A US special forces soldier suspected of having accidentally killed a British aid worker held hostage in Afghanistan could face disciplinary action, officials said .
The serviceman, a member of the elite US Navy SEALs, failed to initially inform his commanding officers that he had tossed a grenade into an insurgent hideout during the operation, two Western officials told AFP.
NATO officers suspect the grenade may have killed Linda Norgrove, who died last Friday in the American rescue bid.
US and NATO officials had initially believed Norgrove was killed when one of her Taliban captors blew up a suicide vest -- but a subsequent military review of the operation suggested she may have been killed by the American's grenade.
Commanders reviewing a video of the operation spotted a SEAL throwing a grenade into the captors' building, said the officials, who spoke on condition of anonymity.
Britain's Guardian newspaper first reported on the role of the US serviceman and details of the rescue, citing sources in Kabul and London.
The US military has ordered an investigation into the incident, and the American SEAL member potentially faces disciplinary action, including over his initial failure to inform superiors about throwing the grenade, officials said.
During the assault on the kidnappers' compound, 36-year-old Norgrove broke away from her captors and lay in the foetal position to avoid harm, the Guardian said.
But the US soldier failed to see her and tossed a fragmentation grenade close to where she was hiding, and it exploded next to her, said the paper.
The rescue was ordered because officials concluded Norgrove's life was in grave danger, with her captors talking about murdering her, based on eavesdropping of radio conversations and other intelligence, the paper reported.
The revelations came as British Prime Minister David Cameron was to meet the top NATO commander in Afghanistan, US General David Petraeus, in London later Thursday. They had been scheduled to hold talks before the incident.
Cameron said Tuesday the circumstances surrounding the aid worker's death were still "unclear."
"The responsibility for Linda's death lies with those cowardly, ruthless people who took her hostage in the first place," he insisted.
In the rescue attempt, the American team moved in before dawn, descending by rope from helicopters, while commanders back at headquarters watched the operation unfold on a live video feed, the Guardian reported.
The US Navy SEAL team was chosen for the rescue because they were familiar with the mountainous terrain in eastern Kunar province and had access to Blackhawk helicopters, better suited for night operations and able to fly at higher altitude, the paper said.