At least 12 people were killed and four others injured in a suicide attack on a police station in Pakistan's northwest Bannu district on Monday morning, according to police and local authorities.
The killed include three policemen, five local residents and four suicide attackers.
Four policemen were also injured in the attack.
Police are searching for a fifth child suicide bomber aged 10 to 12, said a spokesman of Khyber Pakhtunkhwa Province where Bannu falls under jurisdiction.
Four suicide bombers were shot dead by the police in the attack and five local residents were killed during the exchange of firing between the police and the attackers, said the spokesman.
But some local media said that the five local residents were killed by a suicide bomber who blew himself up near a mosque adjacent to the police station.
Waqar Ahmed, district police officer of Bannu, said that three out of the seven wounded policemen including a senior house officer later died at the district headquarters hospital.
According to local authorities and media reports, the attack took place at about 6:30 a.m. local time when a group of 10 to 15 militants tried to storm a police station in Bannu, capital city of Bannu District bordering the militancy-hit tribal area of North Waziristan along the Pak-Afghan border.
The militants are heavily armed with pistols, handgrenades and rocket launchers, said local media, adding that fierce firing and several blasts were heard during the attack.
Some of the attackers fled away after receiving fierce resistance from the police, they said.
Local watchers believe the attack could be a retaliation for the killing of several al-Qaeda leaders by the U.S. drones in Pakistan over the last few days. On Dec. 1, a U.S. drone strike in North Waziristan reportedly killed a Yemeni al-Qaeda leader named Abdul Rehman Azman. In the following two strikes, two other al- Qaeda commanders including Mohammad Almed Almansoor were also reported killed in North Waziristan.