A district police chief was killed in road-side bomb explosion along with his three guards, and three other policemen were hurt in Obe, a district in Herat province
Provincial government spokesperson, Naqibullah Arwin, told a TOLOnews reporter that they were targeted by the road-side mine while on patrol.
Mr Arwin confirmed that the district police chief, Serajuddin, along with other three policemen were killed in the incident.
He said that three other policemen escorting them in another car were wounded.
No groups, including the Taliban have claimed responsibility for the attack.
Improvised Explosive Devices (IEDs) are used by the Taliban to target foreign and Afghan security forces, but civilians are often the main victims.
Insurgent attacks are believed to have increased in some villages in western Afghanistan.
Afghan forces, supported by foreign troops are struggling to bring the Afghan war to an end.