Violence rocked Pakistan's restive northwestern region killing 12 militants, including six in a US drone attack which targeted their vehicle.The drone unleashed six missiles at a vehicle in the lawless North Waziristan tribal region, an area which has witnessed unprecedented wave of UAV strikes this year killing all the six militants travelling in it.In a ramped up US campaign in the region to take out al-Qaeda, Taliban and Haqqani network fighters, 110 such missile strikes have been launched killing more than 100 militants in the area this year.As the US continue to target North Waziristan, Pakistani forces stepped up their anti-militancy campaign in other tribal areas bordering Afghanistan killing six militants, including a commander in three separate gun battles in the restive Swat region.