The soldiers were killed when their convoy was hit by a massive roadside bomb while traveling through the Zhari district in Kandahar province, according to recent reports.
The Kandahar attack took place a day after insurgents detonated a truck bomb outside a NATO base Musa Qala district in Helmand province.
Two Marine Corps Special Operations troops were killed in the district last year, when an Afghan police commander ambushed the Marines during a sit down with local leaders.
The three NATO soldiers based in a unit from Georgia were killed in the most recent attack.
The back-to-back bombings in Kandahar and Helmand provinces are located in the so-called Pashtun heartland of the Taliban insurgency.
That swath of Taliban territory, stretching north from southwest Afghanistan into the eastern part of the country along the Afghan-Pakistan border, is the target of American and coalition forces this final fighting season.
Those areas "are the areas which are the Pashtun heart of the insurgency and those are the ones that we would expect to be most violent," International Security Assistance Forces (ISAF) Deputy Commander British Lt. Gen. Nick Carter, said in March.
The provinces in that Taliban heartland are slated to be the last areas officially handed over to the Afghan National Security Forces (ANSF) by this spring, as part of the transition plan agreed to during NATO's annual conference in Chicago last May, Carter told reporters at the time.
American units in country during this fighting season will take a back seat to ANSF units in combat operations this spring, as U.S. troops prepare to pull out of Afghanistan next year.
Roughly 66,000 American troops remain in Afghanistan, with half of those forces scheduled to withdraw from the country this spring.
The final 32,000 American forces remaining in the country will start coming home following the country's presidential election in April 2014 — officially ending America's combat role.
On Monday, Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey and Gen. Joseph Dunford, the top U.S. commander in Afghanistan, met with NATO defense chiefs on Monday to discuss postwar plans for Afghanistan.
“On Afghanistan, I believe we should seek to provide clear military guidance on the conduct of the remaining 19 months of the ISAF mission," Danish Army Gen. Knud Bartels, head of the alliance's military committee, said Tuesday.
That pending guidance, according to Bartels, "must reflect the importance of maintaining the confidence of the Afghan population and the tempo of transition” into 2014, he told reporters in Brussels on Tuesday.