The Kam Air Boeing 737 travelling from Herat to Kabul vanished from radar screens on Thursday afternoon after requesting permission to divert because of heavy snow storms, officials said.

"The plane was found 35km east of Kabul. We don't know if there are any survivors," the source told AFP on condition of anonymity.

However another source close to the search operation gave a different distance, saying the crash site was 57km from the capital.

Afghan Transport Minister Enayatullah Qasimi refused to comment when contacted by AFP, while officials from the privately-run airline could not be reached.

Nato-led peacekeepers and Afghan forces launched a search for the plane in the country's mountainous terrain after hopes that it had managed to divert to Pakistan were dashed.

Nine Turks and three Americans are thought to be among a number of foreign passengers on the 737 while six of the eight crew members were Russian, officials said.