Afghan and Nato forces say a two-week operation has driven Taleban militants out of a stronghold in the southern province of Panjwayi.
Nato-led forces have faced unexpected Taleban resistance
The British commander of Nato troops in Afghanistan, Lt Gen David Richards, said Operation Medusa had been a "significant success".
He also said he was very confident that troop reinforcements requested from Nato would be arriving this autumn.
Meanwhile, one person died and several were injured in two bomb attacks.
Nato said at least 400 Taleban fighters had been killed in Operation Medusa, the biggest offensive since Nato took over south Afghanistan from US-led forces at the end of July.
The deaths cannot be independently verified.
The operation involved some 2,000 troops in an attempt to clear Taleban fighters from the farming district of Panjwayi, about 25km (15 miles) west of the southern city of Kandahar.
This... clearly shows the capability that Afghan, Nato and coalition forces have when they operate together," Gen Richards told a news conference in Kabul.
He said the Taleban forces would not be allowed to return to the area, and reconstruction work would begin.
The statement comes a day after US-led forces said they had launched a fresh offensive in the south-east of the country.
The 18,500-strong, Nato-led International Security Assistance Force (Isaf) is operating in southern Afghanistan, in addition to about the same number of US troops deployed elsewhere in the country.
Gen Richards also said he was expecting an announcement later this week from the Nato supreme commander on a request for 2,500 reinforcements.
"The call to boost troop levels has come as troops have faced unexpectedly strong resistance from the Taleban, who were ousted from government in 2001.
Suicide attacks are common in parts of Afghanistan
Poland has already agreed to send 1,000 extra soldiers, but they are not due to arrive until February.
"I'm very confident ... that we do have enough to make a real difference here this autumn, setting conditions for a much better 2007," Gen Richards said.
Elsewhere in Afghanistan, two suicide bombers have targeted Nato military convoys, police say.
One outside Kabul injured at least two American soldiers and two Afghans, while an earlier attack near Kandahar city killed one passer-by and injured four others.