The assailants waiting for the vehicle opened fire on the vehicle late Sunday near the Arbi Tabba in Rajanpur, a district in eastern Punjab province.
The deceased include two police officers, two intelligence officers and a civilian informant, security officials said.
After the attack, the terrorists succeeded in fleeing from the spot.
No one immediately claimed responsibility for the attack.
Law enforcement agencies have launched a hunt for the culprits in the area, but no arrest has been made yet.