At least three Nato oil tankers caught fire when some unknown miscreant opened fire on convoy in Balochistan. Sources said on Sunday that incident took place in Dasht area of Mastung district of the province, adding the gunmen were safely managed to escape from the spot after attack. The sources said that levies forces rushed to the spot and cordoned off the area and launched a search operation in the area. No causalities were reported initially, the sources said.