Officials also reported that two Afghan soldiers died in a bombing and several militants were killed in each of three separate clashes with U.S.-led coalition forces, including one close to the capital.
Violence continues unabated in Afghanistan, despite the presence of thousands of extra U.S. and NATO troops and fresh pledges of financial aid to the struggling government under President Hamid Karzai.
Last year, more than 8,000 people were killed in insurgency-related attacks
- the most since the 2001 U.S.-led invasion - and violence has claimed more than 1,700 lives so far this year.
In Saturday's deadliest incident, a roadside bomb hit a coalition convoy west of the main southern city of Kandahar, killing four troops and wounding two others, one seriously.
Coalition spokesman Lt. Col. Paul Fanning said gunmen opened fire on the stricken vehicles and that three Afghans also were hurt. He declined to release the nationality of the troops, who were involved in training Afghan security forces.
To the east, a Polish soldier from the separate NATO-led force died when a bomb hit his patrol shortly after midnight in the Dila district of Paktika province. Jacek Poplawski, a Polish military spokesman in Warsaw, said four other soldiers were wounded, but their lives were not in danger.
The bombings cap a particularly bloody week.
NATO and Afghan troops backed by warplanes on Wednesday attacked up to 400 Taliban militants who had seized Arghandab, a strategic valley dotted with orchards within striking distance of Kandahar.
According to the Defense Ministry, 56 fighters and two Afghan soldiers died during the overnight operation, though the provincial governor put the militants' toll at over 100.
Authorities have entrusted Haji Agha Lalai, head of a commission promoting reconciliation with militants in the region, with disposing of the bodies, which Lalai said were still lying in the fields Friday.
Lalai said families had called him from across Kandahar province and that he had assured them security forces will not arrest them if they try to retrieve the bodies for burial.