Officials said the man did not appear to be targeting Trump or others involved in the trial
A security official said the arrests took place in Zhob district of the province, the Dawn online reported.
The Afghans - identified as Mohammad Bashir, Maulana Noor-ul-Haq, Maulavi Maqbool and Mohammad Ismail - who were found to be injured, were apparently moving to Peshawar for medical treatment when their vehicle was intercepted.
They were shifted to an undisclosed location for interrogation.