Suspected rebels shot and injured four Pakistani police on Saturday in a violence-plagued tribal district near the Afghan border, official said.
Two of the wounded were in a critical condition in hospital following the early morning attack near Miranshah, the main town in North Waziristan tribal district, they said.
The attackers opened fire on a tribal police vehicle and fled, said a local official.
Incidents of violence have occurred almost daily in North Waziristan since bloody clashes between pro-Taleban militants and security forces earlier this month left some 200 people dead.