Suspected Tehreek-e-Taliban gunmen Wednesday set fire to NATO oil tankers in Quetta for the fourth time in a week in an attack the militant group claimed as revenge for deadly US drone attacks. The militants opened fire on a depot housing 40 tankers on the outskirts of Quetta, killing a member of staff and destroying at least 18 vehicles, in the fourth such attack in a week. "There were about eight to 10 attackers. They came in two cars and started shooting tankers and set them on fire," police official Hamid Shakeel told AFP.Tehreek-e-Taliban militants claimed the Quetta attack and other raids this week in which nearly 60 trucks were torched and three people died. They vowed more attacks to disrupt NATO's supply route through Pakistan and to avenge a new wave of US drone strikes. "We claim responsibility for attacking and torching NATO tankers in Quetta today," Tehreek-e-Taliban spokesman Azam Tariq told AFP. "We will further intensify attacks with the intensification of US drone strikes on us." Pakistan authorities have reported 24 attacks since September 3 which have killed more than 140 people.