KABUL (AP) ― It was a risky but successful operation: British and other NATO forces stormed a cave tucked in the mountains before dawn Saturday and rescued two foreign female aid workers and their two Afghan colleagues being held hostage by Taliban-linked militants.

Helicopters, flying under the cover of darkness, ferried the rescue team to extreme northeastern Afghanistan where they suspected the hostages were being held. After confirming the workers were there, they raided the site, killed several militants and freed the hostages, ending their nearly two-week ordeal.

Helen Johnston, 28, from Britain, and Moragwa Oirere, 26, from Kenya, and their two Afghan colleagues were kidnapped on May 22 while traveling on horseback in Badakhshan province. The four work for Medair, a humanitarian non-governmental organization based near Lausanne, Switzerland.

“They were kidnapped by an armed terrorist group with ties to the Taliban,” said Lt. Col. Jimmie Cummings, a spokesman for the U.S.-led military coalition fighting in Afghanistan. “The kidnappers were armed with heavy machine guns, rocket-propelled grenades and AK-47s. ... The hostages were being held in a cave in the mountains.”

Past rescue attempts in Afghanistan have not always gone so well.

In 2009, Sultan Munadi, an Afghan translator kidnapped alongside New York Times reporter Stephen Farrell, was killed in a hail of bullets during a rescue attempt by British commandos. In 2010, the U.S. Navy’s SEAL Team 6 tried to rescue Linda Norgrove, a Scottish aid worker, from her Taliban captors in Afghanistan. She was killed by a grenade thrown in haste by one of the American commandos.

Afghan officials said seven militants were killed during Saturday’s rescue operation, which was launched around 1 a.m.

British Prime Minister David Cameron approved the rescue operation on Friday afternoon after becoming increasingly concerned about the safety of the hostages.

The mission was carried out by British troops in cooperation with other NATO and Afghan forces, Cameron told reporters outside 10 Downing Street in London.

He said it was “extraordinarily difficult” to decide to go ahead with the operation, which involved a “long route march” without being discovered.

“It was an extraordinarily brave, breathtaking even, operation that our troops had to carry out,” Cameron said.

British Army Lt. Gen. Adrian Bradshaw, the deputy commander of the NATO military coalition in Afghanistan, said the rugged area had steep mountains, deep gullies and demanding terrain.

“The hostages are in good health ― we’ve seen all four of them this morning,’’ Bradshaw said, adding they would be reunited with their families soon.

Johnston’s family expressed delight over the news that the aid worker and her colleagues had been freed.

“We are deeply grateful to everyone involved in her rescue, to those who worked tirelessly on her behalf, and to family and friends for their love, prayers and support over the last twelve days,” the family said in a statement.

Medair spokesman Aurilien Demaurex also expressed relief that the aid workers had been rescued and said the company was “immensely grateful to all parties involved in ensuring their swift and safe return.”

Shams ul-Rahman, the deputy governor of Badakhshan province, said the hostages had been held in Gulati, a village in Shahri Buzurg district, near the Tajikistan border.

“Mostly smugglers are based in those areas, but of course the smugglers have the support of the Taliban,” Rahman said.

He said Afghan elders in the area had been working to seek the release of the aid workers.

“A group of elders was about to go to the village and start negotiations,” Rahman said. “Based on intelligence reports that Afghan forces received, a successful operation was conducted that resulted in the release of the hostages and the killing of the kidnappers.”

Separately, a NATO service member died Saturday following an insurgent attack in southern Afghanistan. The coalition released no other details about the death. So far this year, 177 foreign troops have been killed in Afghanistan.

Also in the south, Abdul Salaam, the Taliban’s military leader for three districts in southern Helmand province, was killed Friday in a joint operation by the Afghan and coalition forces in Kajaki district, the provincial governor’s office said Saturday. Abdul Salaam was the brother of Qayum Zakir, a member of Taliban’s leadership council known as the Quetta Shura after the Pakistani city of the same name, said Fared Ahmad Farhang, a spokesman for the police in Helmand province.

In the east, NATO and Afghan forces detained a militant commander who allegedly planned and coordinated an attack on a coalition base in eastern Khost province Friday. Several other insurgents were detained during the operation in Sabari district. Militants detonated a truck bomb outside Forward Operating Base Salerno on Friday, then tried to storm the site, but coalition forces repelled the attack, killing 14 militants. No foreign or Afghan troops were killed.