Pakistani ambassador goes missing
Sources have told the BBC that the ambassador, Tariq Azizuddin, was kidnapped in the Khyber tribal agency close to the Afghan border.
The Pakistani embassy in Kabul says contact was lost with Mr Azizuddin at around 1045 local time (0645 GMT).
Many areas in the border regions between Afghanistan and Pakistan are strongholds of pro-Taleban militants.
Mr Azizuddin was going to Kabul from Peshawar by road when he disappeared.
The BBC's Alastair Leithead in Afghanistan says that police in Pakistan's Khyber Agency said they believed that Mr Azizuddin had been kidnapped.
There were reports on Pakistani television of his car going through a checkpoint without stopping.