A teenage suicide bomber today struck a religious gathering of the Shia community,killing at least 30 people and injuring nearly 200 others in the town of Chakwal in Punjab province,hours after security forces were targeted near the UN office in the heart of Islamabad and 17 persons killed in another suicide attack in north Waziristan. The suicide attacker detonated his explosives near the gate of an Imambargah or prayer hall in Chakwal,some 90 km south of Islamabad,when he was barred from entering the complex by persons guarding the entrance. About 2,000 worshippers had gathered for majlis,a religious ceremony,at the Imambargah when the attack occurred a little after 12.30 pm local time. Thirty people were killed by the blast,state-run APP news agency reported. There was no official word on the incident though witnesses and reporters said nearly 200 people were injured in the blast. Witnesses said the suicide bomber was aged about 16 or 17 years and was dressed in black. TV channels beamed footage of blood and body parts spattered on the wall near the gate of the Imambargah. Earlier reports had said the bomber had managed to enter the Imambargah. Witnesses said the death toll would have been much higher if the attacker had not been stopped at the gate. A massive rescue operation was launched with dozens of ambulances being used to ferry the injured to hospitals in Lahore,Rawalpindi and Islamabad. Officials in a hospital in Chakwal said about 20 of the injured were in a serious condition. Interior Ministry chief Rehman Malik said President Asif Ali Zardari had ordered the deployment two helicopters to shift the injured. Militants have targeted Imambargahs and the minority Shia community in Sindh province in past and the NWFP in the past few months but todays attack was significant as it occurred in the politically crucial Punjab province. Thirty people were killed in a suicide attack on an Imambargah in Peshawar,the capital of the NWFP,in December last year. A total of 35 people were killed in a suicide bombing on a Shia religious gathering in Dera Ghazi Khan in Punjab in February. President Zardari and Prime Minister Yousuf Raza Gilani condemned the attack in Chakwal. The terrorist assault came a day after a suicide bomber struck a paramilitary camp in Islamabad,killing eight security personnel. An AP report quoted Hakimullah Mehsud,a deputy to Pakistani Taliban leader Baitullah Mehsud, as saying his group would carry out two suicide attacks per week in Pakistan like the one in Islamabad on Saturday.