Islamabad, Pakistan (CNN) -- Ten people, including two policemen, were killed Wednesday when a suicide bomber on a motorbike blew himself up in northwest Pakistan, authorities said.
Another 21 people were injured, said Ejaz Ali Khan, the police chief of Swabi district in Khyber Pakhtunkhwa province.
The explosion took place at a public gathering for a political party in the province.
Abdullah Khan, a senior police official in the district, said the gathering was organized by Jamiat-e-Ulama-e-Islam party. The party head, Fazal Ur Rehman, was scheduled to speak at the rally.
Party spokesman, Moulana Amjad Khan, said Rehman was the target of the attack but was unharmed.
Jamiat-e-Ulama-e-Islam was a former coalition partner of the ruling Pakistan Peoples Party.
Security forces have been battling an insurgency led by the Pakistani Taliban in the province, formerly known as the North West Frontier Province.