At least 15 people are killed in a suspected suicide bombing outside a polio vaccination center in the southwestern Pakistani city of Quetta.
Most of the casualties are believed to possess been cops safeguarding the practice.
Armed guards are routine for polio workers in Pakistan, that have become the goal of several lethal attacks by Islamist militants in the past couple of years.
Militants fight polio vaccination, saying this is a Western conspiracy to sterilise Pakistani youngsters.
Afghanistan and Pakistan are the only two states where the condition continues to be endemic.
The explosion occurred as polio workers each day before heading out on their vaccination rounds and security staff were reporting for duty, said a minister in Balochistan state of, Sarfaraz Bugti.
The deputy commissioner, Dawood Khilji in Quetta, said the death toll had climbed with 14 police officers plus one passerby supported deceased.
When they were hit, among the police officers who survived the blast said his team was preparing to leave for assorted neighbourhoods around Quetta.
Mr Khilji told the BBC the polio drive in the state hadn’t been frozen as an outcome of the strike.