KABUL: Gunmen in Afghanistan are demanding money for the release of five aid workers, including two Western women doctors, held in remote mountains and authorities have opened negotiations in the hope of freeing them, an investigator said on Thursday.

The aid workers employed by Swiss-based aid group Medair were making their way from Faizabad city in rugged northeast Badakhshan province on Tuesday to visit flood-stricken areas when they were abducted about half-way to their destination.

“All five aid workers have been carried to the mountainous district of Shahr-e Bozorg and they are keeping them there,” said Sakhidad Haidari, the senior police detective for the remote province.

“We have found their position and we are in negotiation, but that process has not reached any conclusion yet,” Haidari said.

The kidnapping of foreigners has become relatively common in parts of Afghanistan since US forces toppled the Taliban government in 2001.

In 2010, 10 foreign medical workers, including six Americans, were killed in Badakhshan in an attack blamed on insurgents.

Haidari said the gunmen in the latest incident were thought to belong to kidnap and criminal groups who were taking advantage of the difficult terrain and the loose grip on the area of Afghan security forces.

“I don't think that they have any connection with the Taliban or other insurgent groups,” Haidari said.

Police said on Wednesday the aid workers had been travelling by donkey to visit a clinic in Yawan district, where the road had been destroyed by floods caused by melting snow after one of the worst Afghan winters in decades.

Nato-led forces said they were aware of the kidnapping but had no details. Aid groups operating in the area declined to comment citing the sensitivity of the case.