KABUL: An intelligence official says Nato and Afghan forces launched an operation to rescue two female foreign aid workers and their two Afghan colleagues after learning the Taliban planned to kill one of the hostages.

Afghan intelligence spokesman Shafiqullah Tahiri said Sunday the militants hoped the death would pressure negotiators to accept their demand of a $1 million ransom and the release of five of their colleagues.

Nato and Afghan forces launched the helicopter raid to rescue the aid workers in northern Badakhshan province before dawn Saturday. The two women were from Britain and Kenya.

British Prime Minister David Cameron said Saturday that he approved the operation after becoming increasingly concerned about the safety of the hostages.