The seven were killed in a clash with Afghan forces in southeastern Khost province, which then requested support from US-led soldiers late on Monday, Major Mark McCann told reporters.
No coalition or Afghan forces were injured, McCann said on Wednesday in Kabul.
In a separate development, four Afghan soldiers were injured on Wednesday morning in an explosion at the defence ministry headquarters in central Kandahar city, Wali Allah Shahin, Aljazeera correspondent, reporting from Kandahar, said.
The city's police chief accused the perpetrators of the blast as "enemies of Afghanistan".
The blast occurred at about 9am local time. Columns of smoke were seen rising from the site, Shahin reported.
Security officials at the site told Aljazeera that the blast was caused by explosives abandoned at what was a former military site.
Reaction to arrest
However, another security official in Kandahar city said the explosion was a reaction to the recent arrest of two top Taliban commanders.
Officials say the arrest of Mullah
Umar's bodyguard is significant
The Afghan government has confirmed that one of the arrested Taliban members was the bodyguard of Mullah Muhammad Umar.
The arrest is considered significant as the government believes that this could lead the way to Mullah Umar himself, the correspondent said.
Kandahar, near the Pakistani border, was the power base of Mullah Muhammad Umar, who was ousted by a US-led military offensive in late 2001.
Since then, the ethnic Pashtun-dominated province has been the scene of a Taliban-led fighting with continuing attacks on troops, government officials, civilians and aid workers.
An 18,000-strong US-led military force in Afghanistan continues to hunt for members of the Taliban and of Usama bin Ladin's al-Qaida network.