Pakistan has said there is still no news on its ambassador to Afghanistan who is believed to have been kidnapped on Monday.
Mr Azizuddin had travelled by the road to Kabul in the past
The ambassador, Tariq Azizuddin, had been travelling by car from Pakistan to Afghanistan but never arrived at the border, officials say.
A Taleban spokesman said they were responsible for the abduction.
They said they would exchange him for a Taleban commander captured by Pakistani security forces.
But Pakistani officials said there had been no contact with the ambassador or those holding him.
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.
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.
Hundreds of people have been kidnapped in the dangerous border region in recent years - four Pakistani Red Cross workers went missing in the same area a few days ago.
An official of the Khyber agency tribal administration told the BBC that the ambassador went through the Khyber agency without taking a security escort that was waiting for him at the start of the tribal territory.
Correspondents say that such escorts are routinely sent with dignitaries and officials when they travel through tribal areas.
But some travellers dispense with them because they think it makes their movements more noticeable.
Mr Azizuddin is said to have previously travelled to Kabul by road, often without the tribal security escort.