Scores of people from the Khugakhel tribe had blocked the Pakistan-Afghanistan highway here in protest against the unavailability of electricity.
The agitators also pelted stones in retaliation to law enforcement personnel firing shots in the air to disperse the demonstrators.
The peaceful protests were being held by the tribe against the power unavailability in the Landi Kotal subdivision, reports The News International.
The demonstrators held black flags and chanted slogans against Tesco officials for drawn-out load-shedding in the erstwhile Federally Administered Tribal Areas (FATA) region when the police personnel were brought in to disperse the crowd.
The situation went awry when shots were fired in the air by the Khassadar and Levies personnel. Angry protesters pelted stones in retaliation.
They have threatened more protests if the incidents of firing are not investigated by the government.
Activists, however, have alleged that the protests were held against the trading company, National Logistics Cell (NLC) which is owned by the Pakistani army.
"Peaceful protest was held in Landi Kotal, Khyber Agency against the number one trading company NLCs occupancy of transport services and lands. Number one security forces lathi charged and did intense firing on the peaceful protesters. At Landi Kotal Bypass, Khassadars fired upon the women protesters," Ismail Mehsud, a political activist tweeted on Sunday.
Meanwhile, the incident has left two protesters injured, while three personnel have been wounded as well.
The highway was reopened after four hours of the exchange, following talks between the administrative officials and protesters. An agreement has been inked following the incident, and Tesco has ensured to supply electricity for two additional hours in the area. (ANI)