Protesters marched in the northwestern Pakistani city of Bannu on March 26 to demand the release of fellow activists detained over the past week.
The demonstrators belong to the newly established Pashtun Protection Movement, or PTM, which staged a 10-day protest in the capital, Islamabad, in February.
The movement of mainly young activists is demanding an end to what they say are human rights violations in the country's tribal regions.
They call for the removal of military checkpoints and an end to "enforced disappearances" in which suspects are detained without due process.
Similar protests were under way in the city of Swat, in Khyber-Pakhtunkhwa Province, and in Peshawar, the provincial capital.