At least five people were killed on Friday in a bomb blast in Dera Ismail Khan, Aaj News reported.

The bomb exploded close to the route of a police patrol in the city, police official Mohammad Adnan told Reuters.

He added that it was not immediately clear if the incident was the result of a suicide attack or a bomb planted nearby.

At least 21 people were also injured in the incident. The injured persons and bodies have been shifted to the District Headquarters Hospital.

Last month, a policeman was martyred after unknown militants opened fire on a police camp in Dera Ismail Khan.

The same day, two soldiers were martyred in an IED blast in the South Waziristan district.