A bomb explosion ripped through a video shop in a business center of northwest Pakistan on Wednesday, killing three people and wounding three, police said. The blast came as investigators probed who was behind a car bomb that exploded just outside the Danish embassy earlier this week. It could add to concern that Pakistan's efforts to strike peace deals with militants are failing to end violence. Local police chief Abdul Rauf said the latest attack happened in the town of Kohat, about 45 miles south of Peshawar, the capital of North West Frontier Province bordering Afghanistan. He said the dead and injured were taken to a hospital. The blast also damaged other video and CD stores nearby. There was no immediate claim of responsibility, but previous bombings in this volatile region have been blamed on pro-Taleban militants. Just weeks ago, suspected militants sent letters to shop owners in Kohat and elsewhere in the region, warning them to close their businesses. The US has expressed concerns that the two-month-old Pakistani government's efforts to negotiate with some armed groups in the northwest could give hard-liners time to regroup and intensify attacks on US forces across the border in Afghanistan. The government has insisted it will not negotiate with “terrorists” but only Pakistani militants willing to lay down their arms.