At least four inmates have died in a riot at Afghanistan's main top-security prison, a human rights official has told the BBC.
Security forces are not able to enter parts of the prison
The official, who was among negotiators sent into Kabul's Pul-e-Charkhi jail on Monday, said 39 others had been hurt.
It is not clear how the deaths might have occurred. Afghan authorities have so far denied reports of fatalities.
Security forces are surrounding the jail, parts of which were taken over by inmates on Saturday.
Prisoners have issued a list of demands, including better conditions and talks with high-level officials.
The head of Afghanistan's peace and reconciliation commission, Sibghatullah Mojaddedi, held talks with prisoners on Monday.
Afterwards he said he would take the prisoners' demands to the government and that he was hopeful of a peaceful solution.
More than 100 Afghan soldiers and a number of tanks were deployed outside the prison on Monday evening.
Taleban and al-Qaeda members as well as ordinary criminals are involved in the uprising, officials say. Inmates are reported to be armed with knives and makeshift clubs, but not guns.
Prisoners told the private Tolo television station that 14 inmates had been killed and some were on hunger strike.
Afghanistan Human Rights member Feroza Kohistan held talks with prisoners inside the jail along with government and other human rights officials.
She told the BBC that three inmates, one a Pakistani, were dead in Block 2, where the uprising began.
A fourth man, a Tajik, had been killed in Block 1. She did not say how the prisoners died.
On Sunday sources told the BBC that seven people had been killed and 36 injured in the rioting. Officials have denied the reports.
Deputy Justice Minister Mohammed Qasim Hashimzai said on Monday that force would be used if necessary to end the rebellion, although he would prefer a peaceful resolution.
"We can take all these prisoners in one hour," he told the Associated Press news agency.
One Afghan MP, Assadullah Hymatyar, denounced any use of gunfire to quell the unrest, and called for "immediate, peaceful negotiations".
"It's a plot to kill the political prisoners," he told the BBC. "If it's not, then why are they firing at them in the blocks behind closed doors?"
Fears for women
Gunfire was heard within the prison walls on Saturday night and Sunday, but the BBC's Bilal Sarwary in Kabul says the situation was calmer on Monday, with only two gun shots heard, and fewer troops at the scene.
Hundreds of prisoners remain barricaded inside the women's wing.
Senior jail officials say they fear some of the women inmates may have been raped. Two female prison guards are reported to have been taken hostage.
Trouble apparently started at about 2200 (1730 GMT) on Saturday in Block 2 - which houses 1,300 inmates - after a change in prison uniform rules.
By Sunday evening local time, up to 750 inmates jailed for ordinary criminal offences in another block had begun burning furniture in support of the Block 2 prisoners.
Pul-e-Charkhi is a huge prison complex built in the 1970s on the outskirts of the capital.
Correspondents say the vast and run-down jail is notorious for the disappearance and torture of thousands of Afghans during the communist era.
Last month, seven Taleban suspects escaped from the jail, with prison guards accused by officials of helping the break-out.