A suicide bomber blew himself up near a truck carrying police officers on their way to protect polio workers near Quetta Wednesday, killing a police officer and two civilians. The bombing also wounded 23 others, mostly policemen, officials said.

Ghulam Azfer Mehser, a senior police officer, said the attack happened as the policemen were heading to the polio workers, part of a nationwide vaccination drive launched Monday.

The blast was so powerful that it toppled the truck carrying police officers into a ravine, he said, adding that the bombing also damaged a nearby car carrying members of a family.

He said that the anti-polio campaign will continue even after the bombing.

Pakistani President Arif Alvi, Prime Minister Shahbaz Sharif and other officials in separate statements condemned the attack.