500 non-Afghan prisoners seize guns and revolt in the fortress
Northern Alliance soldiers closed roads leading to the fort and Red Cross officials had to turn back because of gunfire.
The International Committee of the Red Cross is trying to assess the extent of casualties, following reports that hundreds of Taleban prisoners had been killed.
In Washington, Pentagon spokeswoman Victoria Clarke said five US military personnel had been injured by a stray American bomb.
The satellite-guided bomb was dropped in an air strike to put down the prisoners' uprising, she said.
Three of the injured servicemen have been rushed to Uzbekistan for medical treatment. None of the injuries are life-threatening, she said.
The BBC's Catherine Davis, reporting from outside the fort, says that Taleban prisoners are still holding out in its southern wing.
Alliance troops involved in the fighting said that the prisoners still alive numbered around 50.
There have been losses among alliance fighters too.
And with gunfire and explosions continuing, our correspondent says there is little sign that the revolt is over.
'Foreigners spared'
Dr Wahid said the Northern Alliance was aware of its international obligations and denied it was using this as an opportunity to get rid of unwanted prisoners.
Foreign fighters have often been beaten or killed when territory has fallen to the Northern Alliance in the course of the current conflict.
But alliance leader Burhanuddin Rabbani has promised that his forces will spare foreigners.
He denied that they were being systematically killed and said they could be handed over to the United Nations.
Dr Wahid said a commission had been formed to disarm the prisoners.
But he said some kept hand grenades and started killing people indiscriminately.
Special forces
A journalist who was near Mazar-e-Sharif during the initial stages of the revolt said American and British special forces were inside the fort, fighting the Taleban prisoners.
He said they went in because they thought an American soldier there had been killed, and another had run out of ammunition.
A US Defence Department spokesman, Lieutenant Colonel Dan Stoneking, confirmed that US special forces troops had been deployed.
He said Northern Alliance commander Abdul Rashid Dostum had also sent in 500 of his men to quell the uprising.
The foreign fighters, believed to have links to the al-Qaeda network of Saudi-born militant Osama Bin Laden, were detained in Qala-e-Jhangi fortress after they surrendered to the alliance outside Kunduz on Saturday.
The fighting began on Sunday when the prisoners killed some of their guards and seized weapons.
Some reports said the prisoners had smuggled guns into the fort and attempted a mass breakout.