epa05099402 A man, who was injured in a bomb blast outside a Polio vaccination center, receives medical treatment at a hospital in Quetta, Pakistan, 13 January 2016. At least 15 people mostly Police were killed when a bomb exploded outside a Polio vaccination center in Quetta. The number of polio-infected children in Pakistan fell significantly in 2015 due to the military's success in pushing back Islamist militants as only 51 new cases were reported in 2015, down from 306 the previous year, as health workers were able to reach areas previously controlled by Taliban insurgents in the north-western tribal areas. EPA/JAMAL TARAQAI ▲ epa05099401 A Pakistani security official, who was injured in a bomb blast outside a Polio vaccination center, receives medical treatment at a hospital in Quetta, Pakistan, 13 January 2016. At least 15 people mostly Police were killed when a bomb exploded outside a Polio vaccination center in Quetta. The number of polio-infected children in Pakistan fell significantly in 2015 due to the military's success in pushing back Islamist militants as only 51 new cases were reported in 2015, down from 306 the previous year, as health workers were able to reach areas previously controlled by Taliban insurgents in the north-western tribal areas. EPA/JAMAL TARAQAI ▲ epa05099404 A Pakistani security official, who was injured in a bomb blast outside a Polio vaccination center, receives medical treatment at a hospital in Quetta, Pakistan, 13 January 2016. At least 15 people mostly Police were killed when a bomb exploded outside a Polio vaccination center in Quetta. The number of polio-infected children in Pakistan fell significantly in 2015 due to the military's success in pushing back Islamist militants as only 51 new cases were reported in 2015, down from 306 the previous year, as health workers were able to reach areas previously controlled by Taliban insurgents in the north-western tribal areas. EPA/JAMAL TARAQAI ▲ epa05099406 Pakistani security officials, who were injured in a bomb blast outside a Polio vaccination center, receive medical treatment at a hospital in Quetta, Pakistan, 13 January 2016. At least 15 people mostly Police were killed when a bomb exploded outside a Polio vaccination center in Quetta. The number of polio-infected children in Pakistan fell significantly in 2015 due to the military's success in pushing back Islamist militants as only 51 new cases were reported in 2015, down from 306 the previous year, as health workers were able to reach areas previously controlled by Taliban insurgents in the north-western tribal areas. EPA/JAMAL TARAQAI ▲ epa05099405 Bodies of the victims of a bomb blast outside a Polio vaccination center, are brought to a mortuary in Quetta, Pakistan, 13 January 2016. At least 15 people mostly Police were killed when a bomb exploded outside a Polio vaccination center in Quetta. The number of polio-infected children in Pakistan fell significantly in 2015 due to the military's success in pushing back Islamist militants as only 51 new cases were reported in 2015, down from 306 the previous year, as health workers were able to reach areas previously controlled by Taliban insurgents in the north-western tribal areas. EPA/JAMAL TARAQAI ATTENTION EDITORS: GRAPHIC CONTENT ▲ epa05099403 A Pakistani security official, who was injured in a bomb blast outside a Polio vaccination center, receives medical treatment at a hospital in Quetta, Pakistan, 13 January 2016. At least 15 people mostly Police were killed when a bomb exploded outside a Polio vaccination center in Quetta. The number of polio-infected children in Pakistan fell significantly in 2015 due to the military's success in pushing back Islamist militants as only 51 new cases were reported in 2015, down from 306 the previous year, as health workers were able to reach areas previously controlled by Taliban insurgents in the north-western tribal areas. EPA/JAMAL TARAQAI ▲ epa05099417 Pakistani security officials inspect the scene of a bomb blast that targeted a Polio vaccination center in Quetta, Pakistan, 13 January 2016. At least 15 people mostly Police were killed when a bomb exploded outside a Polio vaccination center in Quetta. The number of polio-infected children in Pakistan fell significantly in 2015 due to the military's success in pushing back Islamist militants as only 51 new cases were reported in 2015, down from 306 the previous year, as health workers were able to reach areas previously controlled by Taliban insurgents in the north-western tribal areas. EPA/JAMAL TARAQAI ▲ epa05099420 Pakistani security officials collect belongings of their comrades from the scene of a bomb blast that targeted a Polio vaccination center in Quetta, Pakistan, 13 January 2016. At least 15 people mostly Police were killed when a bomb exploded outside a Polio vaccination center in Quetta. The number of polio-infected children in Pakistan fell significantly in 2015 due to the military's success in pushing back Islamist militants as only 51 new cases were reported in 2015, down from 306 the previous year, as health workers were able to reach areas previously controlled by Taliban insurgents in the north-western tribal areas. EPA/JAMAL TARAQAI ▲ epa05099418 Pakistani security officials inspect the scene of a bomb blast that targeted a Polio vaccination center in Quetta, Pakistan, 13 January 2016. At least 15 people mostly Police were killed when a bomb exploded outside a Polio vaccination center in Quetta. The number of polio-infected children in Pakistan fell significantly in 2015 due to the military's success in pushing back Islamist militants as only 51 new cases were reported in 2015, down from 306 the previous year, as health workers were able to reach areas previously controlled by Taliban insurgents in the north-western tribal areas. EPA/JAMAL TARAQAI ▲ epa05099415 Pakistani security officials collect belongings of their comrades from the scene of a bomb blast that targeted a Polio vaccination center in Quetta, Pakistan, 13 January 2016. At least 15 people mostly Police were killed when a bomb exploded outside a Polio vaccination center in Quetta. The number of polio-infected children in Pakistan fell significantly in 2015 due to the military's success in pushing back Islamist militants as only 51 new cases were reported in 2015, down from 306 the previous year, as health workers were able to reach areas previously controlled by Taliban insurgents in the north-western tribal areas. EPA/JAMAL TARAQAI ▲ epa05099414 Pakistani security officials inspect the scene of a bomb blast that targeted a Polio vaccination center in Quetta, Pakistan, 13 January 2016. At least 15 people mostly Police were killed when a bomb exploded outside a Polio vaccination center in Quetta. The number of polio-infected children in Pakistan fell significantly in 2015 due to the military's success in pushing back Islamist militants as only 51 new cases were reported in 2015, down from 306 the previous year, as health workers were able to reach areas previously controlled by Taliban insurgents in the north-western tribal areas. EPA/JAMAL TARAQAI ▲ epa05099416 Pakistani rescue workers climb into the Polio Vaccination center from the rear side after a bomb blast that targeted a Polio vaccination center in Quetta, Pakistan, 13 January 2016. At least 15 people mostly Police were killed when a bomb exploded outside a Polio vaccination center in Quetta. The number of polio-infected children in Pakistan fell significantly in 2015 due to the military's success in pushing back Islamist militants as only 51 new cases were reported in 2015, down from 306 the previous year, as health workers were able to reach areas previously controlled by Taliban insurgents in the north-western tribal areas. EPA/JAMAL TARAQAI ▲ epa05099432 Pakistani security officials collect belongings of their comrades from the scene of a bomb blast that targeted a Polio vaccination center in Quetta, Pakistan, 13 January 2016. At least 15 people mostly Police were killed when a bomb exploded outside a Polio vaccination center in Quetta. The number of polio-infected children in Pakistan fell significantly in 2015 due to the military's success in pushing back Islamist militants as only 51 new cases were reported in 2015, down from 306 the previous year, as health workers were able to reach areas previously controlled by Taliban insurgents in the north-western tribal areas. EPA/JAMAL TARAQAI ▲ Il gruppo armato talebano Tehrik e Taliban Pakistan ha rivendicato su Twitter l'attentato a un centro antipolio di Quetta , capoluogo della provincia del Baluchistan, nel quale sono morte quindici persone - delle quali tredici sono poliziotti - e dieci sono rimaste ferite in seguito a una forte esplosione.