The Afghan government says it was wrong to have claimed to have captured two senior Taleban commanders during fighting for the town of Musa Qala.
On Sunday the defence ministry said it had captured Mullah Matin and Mullah Rahim, both well-known Taleban commanders in Helmand province.
But now the ministry says that it was a case of mistaken identity.
A ministry spokesman said no Afghan soldiers were killed in operation and that only four civilians died.
Afghan forces - with British and American support - say they have now secured the centre of Musa Qala after going through it street by street.
Local people, contacted by phone before a mobile communication mast was destroyed in bombing, said the losses sustained by Afghan, British and American troops were far higher than they had admitted.
The BBC's David Loyn in Kabul says that Afghan soldiers supported by British and American troops went through the town cautiously, compound by compound.
Map showing how assault on Musa Qala took place
A British spokesman said there had been some isolated incidents of shooting but the main body of the Taleban appeared to have left when their order came to withdraw on Monday.
Although the provincial governor had earlier appealed for people to return to their homes, the Afghan spokesman said it would not be safe in Musa Qala for a further 48 hours, while the last remnants of the Taleban were cleared and the area was checked for mines.
Afghanistan's President Hamid Karzai earlier said that he needed more help from the international community to help build his country's armed forces.
Mr Karzai's comments come despite Afghan troops taking the lead in retaking Musa Qala from the Taleban.
The Afghan defence ministry recently said that the Afghan armed forces needed to be 200,000 strong.
But our correspondent says there is no international support for that figure.
In 2001 the international community agreed to fund an army of 70,000 men.
It will reach that total soon and most will be equipped with US-made M-16 rifles.
World-class helicopters and tanks are also being supplied from abroad.
The Afghan government wants a larger army, not just to put down the Taleban insurgency, our correspondent says, but also to be able to project a more assertive posture in the region, with instability threatening to spill over from Pakistan to the east.
To the west, Iran has an army that is 350,000 strong, but most of that is made up of conscripts.
Some ministers, including the acting counter-narcotics minister, Gen Khodaidad, who was an officer in the Soviet-backed army in the 1980s, say compulsory conscription is the only way for Afghanistan to fulfil its defence needs at the same time as helping to build a national identity.
Mr Karzai has rejected these demands.
Speaking at a Kabul press conference on Monday, he said the decision to attack Musa Qala followed reports of atrocities being perpetrated by the insurgents in the town.