Suspected Islamic militants beheaded two women in northwest Pakistan after accusing them of being prostitutes, police said Friday.

Villagers spotted the decapitated bodies on the outskirts of Bannu, a city in a region where extremists are waging a violent campaign to impose Taliban-style social norms, a police official said.

The two women, 28 and 30, were riding an auto rickshaw when five armed men, wearing masks, overpowered them, bundled them into a car and drove away, he said, quoting witnesses.

The official asked for anonymity because he was not authorized to speak to the media.

A note found with the bodies identified the victims as Bannu residents and accused them of "doing acts of obscenity," a term meaning prostitution, according to the police official.

"We have started doing this to end obscenity in the area," the official quoted the unidentified assailants as saying in the note.

Authorities will investigate the slayings, he said.

Extremists have bombed shops selling music and movies in Bannu and other towns in North West Frontier Province, and barbers have been warned not to shave customers' beards — moves reminiscent of the harsh version of Islamic law once imposed by the Taliban in neighboring Afghanistan.

In Mingora, a town south of Bannu, a powerful bomb blast Friday destroyed 48 shops, 33 of them selling music and movie CDs, a local police official said. No one was hurt in the attack.

The pre-dawn explosion damaged the gates of the shops and scattered CDs in the downtown market, the official said on condition of anonymity because he was unauthorized to make media comments.

Music shops in the market had received warnings in the past from suspected militants to close their businesses, he said.

Meanwhile, suspected militants shot dead the son and a nephew of a pro-government tribal elder in Bajur, a tribally governed region bordering Afghanistan, local security official Tor Khan said.

Two masked gunmen on a motorcycle opened fire on the two men in Lagharay, a village near Bajur's main town of Khar, Khan said.

Militants have killed scores of tribesmen and beheaded some of them in the border region after accusing them of collaborating with Pakistani security authorities or spying for the United States.