In southern Kandahar province, meanwhile, a roadside bomb hit a police patrol vehicle Friday, killing four policemen, said Zhari district chief Niaz Mohammad Serhadi.
The southern provinces have been the arena of the heaviest fighting between insurgents and international forces in recent months.
During an operation in the Derawud district of Uruzgan province, Afghan and foreign troops battled militants Thursday night, killing 20 suspected Taliban, said Uruzgan police chief Juma Gul Himat. Two policemen were also killed in the fighting.
NATO's International Security Assistance Force said it was aware of ongoing fighting in the area, but did not have any details.
A separate group of Taliban insurgents poured into the nearby district of Naish, and police surrounded the area on Thursday, triggering a two-hour gun battle that left five suspected militants dead and two policemen wounded, Himat said.
More than 5,800 people, mostly militants, have died in insurgency-related violence this year, a record number, according to an Associated Press tally of figures from Western and Afghan officials.
In southwestern Nimroz province, a suicide bomber blew himself up next to a NATO convoy, but there were no casualties, said ISAF spokesman Maj. Charles Anthony.
Also in Kandahar, militants opened fire on an SUV carrying two newlywed couples and their relatives on Friday, killing both couples and a child, said Kandahar provincial police chief Syed Agha Saqib. Another man and child were wounded.
Saqib blamed the Taliban, accusing them of "killing innocent Afghans."