A blast at the office of a Pakistani political party injured 10 people in the country's northwestern tribal belt Tuesday, as the campaign for nationwide polls on July 25 picks up pace.
The explosion occurred at the office of cricketer-turned-politician Imran Khan's Pakistan Tehreek-e-Insaaf (PTI), or Pakistan Movement for Justice party, which is one of the main challengers to the incumbent Pakistan Muslim League-Nawaz (PML-N).
"A huge explosion happened when I was inaugurating my election office in Razmak city," Malik Aurangzeb Khan, PTI's candidate from the North Waziristan tribal district bordering Afghanistan, told AFP.
"At least 10 people were injured in the blast," he said, adding he could not confirm the nature of the explosion.
A local administration official told AFP on condition of anonymity that an unidentified person threw a grenade at the gathering. A security source also confirmed the attack.
There was no immediate claim by any militant groups for the blast.
North Waziristan is one of Pakistan's seven tribal districts bordering Afghanistan, a region long rife with militancy.
But the Pakistani army has conducted a series of operations there in recent years and claims to have flushed the militants out, with the region set to be merged with Khyber Pakhtunkhwa province.
The U.S. has repeatedly accused Pakistan of allowing the tribal areas to harbour militants fighting in Afghanistan — an allegation Islamabad has consistently denied.
Pakistan is set to complete its second ever democratic transition when voters go to the polls on July 25, with PTI's Khan one of the main candidates to lead the next civilian government in a country that has been ruled by the military for roughly half its 70-year history.