Suspected Taleban militants have killed three policemen in an attack in southern Afghanistan, police say.
The Taleban have increased attacks in recent months
One militant was also killed in the fighting which broke out after militants attacked a police checkpoint outside Kandahar on Saturday.
The attack comes two days before the inauguration of Afghanistan's new parliament, for which security has been beefed up.
More than 1,400 people have died in violence in Afghanistan this year.
A local police official said they were searching the area for militants, who attacked the police checkpoint on the main road linking Kabul with Kandahar.
"According to our information, about 30 Taleban participated in the attack, and they fled after facing a strong resistance," Ghulam Nabi Mullahkhel told the Associated Press news agency.
Suspected Taleban militants have carried out a number of attacks across Afghanistan recently.
President Hamid Karzai has appealed for an end to fighting.
Last month he told a meeting of government leaders and security officials: "It is our wish that all our countrymen... join this [reconciliation] program...to give up destroying their country and participate in its reconstruction."