A suicide attacker struck a police convoy in the western Afghan city of Herat on Sunday killing four police, while a second bomb blast hit a police convoy in southern Kandahar, officials said.
The suicide car bomb hit on the road to Herat's airport, said deputy provincial police chief Delawar Shah Delawar.
"Four policemen were martyred and another officer was wounded," said Ziauldin Mahmmodi, deputy police chief for western Afghanistan.
He said a female police officer was among the dead.
Eyewitnesses at the scene said that the bomber drove his explosives-laden car into the police convoy.
Two fuel tankers were alight at the scene, along with a damaged police pick-up truck.
Herat is a relatively peaceful province compared to the troubled southern region of the country where insurgents in Helmand and Kandahar provinces carry out regular attacks against Afghan and international troops.
In Kandahar city, explosives fixed to a parked motorcycle detonated as a prison police convoy passed, injuring one policeman, deputy provincial police chief Fazel Ahmad Shairzad said.