Taleban fighters are still holding out
Anti-Taleban commanders said that they had pulled back their soldiers to allow US planes to step up raids on Taleban and al-Qaeda positions around the airport.
US Secretary of Defence Donald Rumsfeld said that if the Taleban did not surrender control of the city, the US was prepared to use force if necessary to obtain it.
"The situation in Kandahar is complicated," he told reporters. "It's not easy, but one thing is clear: The Taleban and al-Qaeda will be driven from Kandahar."
US ground forces in the area have been patrolling the area, to prevent Taleban fighters from escaping.
Pentagon officials confirmed that a member of US special forces was shot and injured near Kandahar on Tuesday. His condition is reported to be stable.
Mr Rumsfeld accused the Taleban of using Kandahar's civilian population as "human shields".
Taleban defiance
Ahmad Karzai, brother of Afghanistan's newly-nominated transitional leader Hamid Karzai, said there had been heavy clashes between Pashtun tribesmen loyal to former Kandahar governor Gul Agha and Taleban troops.
"Gul Agha's men
tried to enter the airport itself, but they could not," he told Reuters news agency.
"They are now back where they were, on the banks of the river about one or two kilometres from the centre of the airport."
A spokesman for Gul Agha's men said they had withdrawn so that the US could continue to bomb the area.
"People like Gul Agha wouldn't be a problem for us" if it were not for the air strikes, said Mullah Qasim, a Taliban commander south of Kandahar.
"We could push him back not in days, but hours."
Cave advance
In the east of the country, anti-Taleban forces have advanced towards the caves in the Tora Bora mountains, where Osama Bin Laden - accused of masterminding the 11 September attacks on the United States - is thought to be in hiding.
Hundreds of fighters set out from the town of Jalalabad on Tuesday, intent on reaching the area around Tora Bora, about 55
kilometres (35 miles) south of Jalalabad.
According to one commander, hundreds of anti-Taleban fighters travelling from Jalalabad have met no opposition.
"Bombing continues," Hazrat Ali, in Jalalabad, told Reuters. "We have taken some areas which they [Bin Laden's men] left around Tora Bora. They pulled out from these areas without a fight."
Part of the cave complex is now reportedly held by anti-Taleban forces.
Mr Ali said everything was now being put in place for a final assault, but warned that the attack was being delayed whilst his troops ensured that they were not inadvertently hit by US air strikes.
"Yesterday, American planes were about to bomb civilians and our people and we want to make sure that they can identify our men, " Mr Ali said.
He added that US air strikes had killed at least 12 members of Bin Laden's al-Qaeda network in or around Tora Bora in the last two days.