QUETTA - A suicide bomber yesterday killed at least 16 people, 13 of them policemen, outside a polio-eradication centre in Quetta.

The bomb blew up a police van that had just arrived at the centre to provide an escort for workers in a drive to immunise children under five. The attack killed at least 13 policemen, one paramilitary officer and two civilians, officials said, adding 25 people were wounded.

At least three vehicles were also blown up in the explosion, while human remains lay strewn across the area, along with items of clothing, including caps and shoes of policemen.

The law-enforcement agencies and rescue teams rushed to the site and shifted the dead and injured to Civil Hospital. The condition of eight injured was reported critical by the paramedics at the hospital. The law enforcers cordoned off the area and launched a search operation.

Balochistan Home Minister Sarfaraz Bugti, confirming the incident, said the personnel of law-enforcement agencies were among the dead and injured. He said: “We are living in a conflict zone and hostile agencies are targeting us. It is a conflict zone and hostile agencies have been carrying out sabotage acts after China-Pakistan Economic Corridor (CPEC) and other mega projects were announced in the region.” Bugti said it was being investigated whether it was a suicide attack or a bomb blast.

Some officials began to gather evidence from the scene while others were collecting body parts. Eyewitness Shabbir Ahmed, a 32-year-old police constable, said he had been deployed to protect a polio-vaccination team that was due to leave for various neighbourhoods of Quetta at 10am. “Suddenly, there was a loud bang and I fell to the ground, I could not see anything, there was dust everywhere. Then I heard people screaming and sirens of ambulances,” he continued, adding he had received shrapnel wounds to his stomach, hands, legs and feet.

“It was a suicide blast; we have gathered evidence from the scene,” Balochistan IGP Ahsan Mehboob said. “The police team had arrived to escort teams for the polio campaign,” he confirmed.

Pakistani Taliban and Jundullah separately claimed responsibility for the attack. Ahmed Marwat, a commander and spokesman for Jundullah, said his group was responsible for the attack. “We claim the bomb blast on the polio office. In the coming days, we will make more attacks on polio vaccination offices and workers,” he said by telephone. The Pakistani Taliban also claimed responsibility in a statement released by their spokesman, Mohammad Khorasani.

The teams working to immunise children in Pakistan against polio are often targeted by Taliban and other militants who say the campaign is a cover for Western spies or accuse workers of distributing drugs designed to sterilise children.

Pakistan and neighbouring Afghanistan are the only two countries in the world where polio remains endemic, the World Health Organization says.

The campaign to eradicate the virus in Pakistan has had some recent success, with new cases down last year, but violence against vaccination workers has slowed the effort. In 2014 the number of polio cases recorded in Pakistan soared to 306, the highest in 14 years, falling to 52 in 2015.

Islamist opposition to all forms of inoculation mounted after the CIA organised a fake vaccination drive to help track down Al-Qaeda leader Osama bin Laden in Abbottabad.

Balochistan, Pakistan’s largest, but most impoverished province, is also home to an insurgency that has claimed the lives of hundreds of soldiers and militants since it reignited in 2004, with rebels often attacking government installations and personnel.