An explosion followed by firing was reported on Chaman's Mall Road on Friday afternoon.
Explosives fitted in a parked motorcycle were detonated through a remote control, the police told media.
According to the police, a vehicle belonging to law enforcement agencies was targetted in the incident. The vehicle, along with other private cars, were damaged after the explosion took place.
At least four individuals who were injured in the incident were shifted to the Civil Hospital for medical treatment, two of which are reported critical.
Internet services were suspended an hour before the incident took place after law enforcement agencies received information about a security threat.
The Mall Road is a busy road with important offices located in the vicinity including the police's Special Branch office, the City Police Station, a Frontier Corps check post. The additional deputy commissioner - revenue also resides in the same vicinity.
Public property — including over ten shops — was partially destroyed in the incident.
Security forces have cordoned off the area and investigations into the incident are under way.
The incident comes amid fast-approaching polls, due to be held on July 25.
A spate of terrorist attacks has taken place in the current month. On July 10, a bomb targeted a rally by the Awami National Party (ANP) in Peshawar, martyring local party leader Haroon Bilour along with 21 others.
An attack on a Jamiat Ulema-e-Islam-Fazl (JUI-F) convoy in Bannu on July 13 followed the tragic Peshawar incident. The Bannu incident claimed lives of at least four people, while 10 others were injured in the explosion.
Later the same day, in what was one of the deadliest terrorist attacks in the country's history, Balochistan Awami Party (BAP) candidate Nawab Siraj Raisani along with 131 others was martyred when a suicide bomber blew himself up during an election rally in Mastung's Darengarh area.
On July 16, ANP leader Daud Khan Achakzai was injured after unknown persons opened fire on the guest house of the party's candidate Zmrak Khan Achakzai in Chaman.