DERA ISMAIL KHAN  -  A mourning day was observed in Dera Ismail Khan on Monday in commemoration of the victims of ThoyaFazil and Commissionery Bazaarbombings which claimed 13 lives, besides leaving more than 150 people injured. Leaders of Ahle Sunnat and Shiasects had jointly given the mourning call.  No hustle bustle was seen in the city and major trading and shopping remained closed on Monday while low attendance was observed in offices. Private educational institutions also remained closed. Though ban on pillion riding was lifted, traffic on road was sparse. Police have registered a case against unknown militants and started investigation.Monitoring Desk adds: An expolsion near a Muharram procession in Commissionary Bazaar on early Sunday killed five people, besides injuring 70 others.Tehrik-i-Taliban spokesperson Ehsanullah Ehsan while talking to a TV channel claimed that the militant organisation was behind the attack.He said that it was a suicide attack. Ehsan declared that the TTP would keep hitting its targets, outdoing the efforts of the interior minister.Khyber Pakhtunkhwa Information Minister Mian Iftikhar Hussain confirmed the number of casualties, adding that women, children and security personnel, were among the injured. He said that security was beefed up after the explosion on 9 Muharram but the terrorists managed to plant the bomb. He said that those found guilty of negligence would be punished. He said that the nature of the explosion could only be determined after the submission of the bomb disposal squad’s report.An emergency was imposed in DI District Headquarters Hospital and, according to doctors, some of the injured were in critical condition. The rescue personnel reported that a gas cylinder was recovered near the site of explosion.Security personnel cordoned off the site of explosion before starting investigations and barred reporters from inspecting the scene.Earlier, a bomb blast on Saturday killed eight people near a mourning procession in the same city. The banned TTP had also claimed responsibilityfor the bombing.Interior Minister Rehman Malik had suspended cellular service in major cities during Ashura to prevent such bombings which often use cellphones as detonators.