The attackers, travelling on a motorcycle, opened fire on a police car in Khyber Pakhtunkhwa province

TL;DR

Suspected militants riding a motorcycle shot and killed two police officers assigned to protect polio workers during a door-to-door vaccination campaign Tuesday in northwestern Pakistan, officials said. The drive-by shooting in Mohmand, a district in Khyber Pakhtunkhwa province that borders Afghanistan, also wounded a third officer.