DERA ISMAIL KHAN - At least 10 people, including four security men and two journalists, were killed and 28 others injured seriously in twin bomb blasts in front of Polytechnic College here on Sunday. Ten minutes before the explosion, a hand-grenade blew up in the area and when rescue workers reached the site, a powerful bomb, planted in a vehicle of Rescue 15, exploded with a huge bang, leaving ten people, including four security men and two journalists dead. It is believed that a suicide bomber was inside the vehicle. But it is not clear whether the vehicle, stated to be of Rescue 15, was stolen or fake one. However, all the injured were later rushed to the District Headquarters Hospital, where most of them were stated to be in critical condition. It is important to mention here that security personnel were camped inside the Polytechnic College where they had established a checkpost. The explosion was of high-intensity which jolted the entire city and created panic among the residents. Soon after the blast, rescue workers, police, officials of secret agencies and Bomb Disposal Squad reached the site and started relief activities, but work halted for some time because of power outage. Bomb Disposal Squad collected the remains of the bomb for examination. Security has been beefed up and everyone entering the city is being thoroughly frisked by the security forces. Meanwhile, President Asif Ali Zardari, Prime Minister Yousuf Raza Gilani, NWFP Chief Minister Amir Haider Khan Hoti, Punjab Chief Minister Shahbaz Sharif and Advisor to Prime Minister on Interior Rahman Malik have strongly condemned the tragic incident. The President and the Prime Minister ordered for timely investigation of the blast and directed the hospital authorities to provide the best possible treatment to the victims. AFP adds: A teenaged suicide bomber carried out the attack on police in DI Khan as they were investigating an earlier blast, killing seven people and wounding 28 others, officials said. The attack took place on a busy road in the town where police were called to the scene of a minor grenade explosion, District Coordination Officer Syed Mohsin Shah told AFP, saying that five police and two civilians were killed in the suicide attack. No one immediately claimed responsibility for the blast, the latest in a wave of suicide and other attacks across Pakistan that have left more than 1,500 people dead in the past 18 months. A member of the bomb squad called in to investigate told AFP that fragments of a suicide jacket and an unexploded hand-grenade were found at the scene, adding that 10 to 15 kilos of explosives were likely detonated. "The bomber was between 15 and 18 years old," Shah said. Ashiq Saleem, the chief of the main government hospital in Dera Ismail Khan, told AFP that a head and foot believed to belong to the suicide bomber had been brought in for analysis. President Asif Ali Zardari condemned what he called a "cowardly act of terrorism" and expressed his condolences to the families of those killed, in a statement carried by the APP. Later, gunmen opened fire on an ambulance transporting one of the bodies from the hospital to the victim's home, wounding the driver and two of the victim's relatives, a local official said. The assailants fled the scene. Our Monitoring Desk adds: FC troops were deployed there for maintaining law and order during Muharram. The dead journalists have been identified as Dr Saleem Awan and Imran Ahmed.