LONDON, Oct 9: Afghan gunmen killed a British woman during a raid by US troops which was launched because her life was considered to be in grave danger, Britain's foreign minister said on Saturday.

Several militants were killed in Friday's attempt to free 36-year-old Linda Norgrove. She and three Afghan colleagues were abducted last month in rugged eastern Kunar province, where militant activity is high.

According to an Afghan intelligence official, the rescue team was closing in on the house where Ms Norgrove was being held when her captors threw a grenade into the room where she was kept, killing her. The troops opened fire and killed all the captors, the official said.

“It is with deep sadness that I must confirm that Linda Norgrove, the British aid worker... was killed at the hands of her captors in the course of a rescue attempt last night,” Foreign Secretary William Hague said in a statement.

A Foreign Office source said US forces conducted the rescue attempt and that no British troops were involved. Media said that American special forces had mounted the operation.

Ms Norgrove was abducted on Sept 26 but there had been a media blackout in order not to raise the value of the worker in the eyes of her captors.

It was unclear whether the Taliban were behind the kidnapping.

This year has been the most violent in the nine-year Nato-led campaign against Taliban militants in Afghanistan, and in August gunmen killed eight foreign medical workers, including British surgeon Karen Woo.

Born in Scotland, Ms Norgrove was regional director of a USAID project designed to create jobs and strengthen the economy, a plan seen as key to robbing the Taliban of support among the Afghan population. She spoke Dari.—Agencies