Police has confirmed the death of at least seven people and 50 injured persons by a bomb attack on a religious school in the Pakistani city of Peshawar.

Apart from dozens of injured people, including four under the age of 13, hospital officials say those killed were young men, aged between 20 and 30.

So far, the motive for the attack on a Koran study class is unclear as Hundreds of students were present at the seminary.

Meanwhile, the reports earlier suggested four of the dead were children, but this has since been retracted.

While investigation is on, no group has admitted it carried out the attack.

The northern city of Peshawar, close to the Afghan border, has seen some of the worst of the violence during the Taliban insurgency in recent years.

Going memory lane, gunmen stormed a military school in the city leaving more than 150 dead, most of them children six years ago.

However, an army crackdown in the years which followed resulted in the number of attacks being greatly reduced inside Pakistan.