KHAR, Pakistan - A bomb exploded in a market in Pakistan's Bajaur tribal region on the Afghan border on Saturday, killing five civilians and wounding 10, officials said.Pakistan has seen a surge in militant violence since al-Qaida chief Osama bin Laden was killed in a US raid in a northern Pakistani town on May 2. Pakistani Taliban militants allied with al-Qaida have vowed to avenge bin Laden's killing.The latest blast occurred in Salarza area, about 15 km (9 miles) north of region's main town of Khar."The explosive was planted somewhere in a restaurant. Many people were there when it exploded," Saad Mohammad, a government official in the region, told Reuters.He said five people were killed in the blast. Residents have formed a tribal force to fight Taliban militants in the area that borders Afghanistan.A suicide car bomber killed 27 people in an attack outside a police station in the northwestern city of Hangu on Thursday.Early this week, Taliban assaulted a heavily guarded naval base in the southern city of Karachi. Ten military personnel were killed and two aircraft destroyed in the attack.