A powerful bomb exploded near a vehicle carrying police officers in northwestern Pakistan on Sunday, killing at least two officers and injuring three others, police said. The attack happened near a roadside open market in Peshawar, the capital of Khyber Pakhtunkhwa province, a local police chief, Masood Khan, said. No one immediately claimed responsibility for the attack, but suspicion is likely to fall on the Pakistani Taliban, also known as Tehreek-e-Taliban Pakistan, or TTP, who often target security forces and civilians.