Major General Athar Abbas, a Pakistan army spokesman, on Friday said the army was investigating the alleged abuse, but declined to comment further.
Pakistan's poorly trained and underfunded security forces have been accused of human rights abuses before.
The independent Human Rights Commission of Pakistan said in an August report it had received "credible reports of numerous extrajudicial killings and reprisals carried out by security forces" in the Swat Valley since the area was retaken from Taliban control in July.
It was not clear where or when the video was shot, and its authenticity was impossible to verify.
In the video, one officer quizzes a man over whether his brother-in-law is an anti-government fighter.
|Many of the men were first questioned before being dragged and kicked to the ground
The man says he does not know. The officer then signals for his deputies to begin attacking the suspect. He is punched, lashed with a leather rope and kicked repeatedly while on the ground.
He screams "Have mercy on me, oh God" in Pashto, the language of the
northwestern tribal areas close to the Afghan border where the Pakistan army is engaged in anti-Taliban offensives.
Two of the men who were beaten appeared to be in their 50s.
Under US pressure, the Pakistani army is fighting in several areas of the northwest, where al-Qaada and Taliban are strong.