About a dozen armed militants attacked a Pakistani police checkpoint on a highway in the restive Khyber Pakhtunkhwa province before dawn today, killing three police officers and a civilian before fleeing the scene, authorities said.<br />''<br />''The attack on the Lachi checkpoint along the Indus Highway in Kohat district, bordering Afghanistan, triggered a shootout. Officers returned fire and a search is underway to find the assailants.<br />''<br />''No one immediately claimed responsibility for the attack, but suspicion is likely to fall on the Pakistani Taliban, who often target security forces across the country, especially in the northwest near the Afghan border.<br />''<br />''The latest attack was the third on police in the past three days in Khyber Pakhtunkhwa province, bringing to 12 the number of officers killed so far there. <br />