A suicide bomber struck a check post in northwestern Pakistan early Monday, injuring at least 19 policemen, two of them critically, police said.
Local TV channels quoted police sources as saying that a suicide bomber tried to ram a mini-truck into the Baraakpul police check-post near Bannu of the North West Frontier Province (NWFP) when around 30 security personnel were present in the building.
The suicider blew up himself some 16 meters away from the check-post when security forces opened fire on him.
Those who sustained injuries in the blast have been shifted to nearby hospitals.
Earlier, local TV channels reported that three policemen were killed.
No group claimed responsibility for the attack.
Police have cordoned off the area and heavy contingents have been deployed.