Tripoli, Libya (CNN) -- At least 50,000 people, civilians and combatants, have been killed in Libya's six-month war to oust Moammar Gadhafi, a rebel military commander told CNN on Tuesday.
The number was calculated by adding death tolls reported in battle zones and accounts from agencies such as the Red Cross, said Hisham Abu Hajer, the Tripoli Brigades coordinator.
The threat of more bloodshed loomed as reports of human rights violations surfaced and the leader of Libya's National Transitional Council issued an ultimatum Tuesday for tribal leaders in towns still under the control of loyalists: Surrender or face attack on Saturday, after Eid al-Fitr festivities have drawn to a close.
NTC head Mustafa Abdul Jalil told reporters that the rebels were in negotiations with the loyalists and hoped to "avoid more bloodshed and to avoid more destruction and damage," but would use force if the loyalists don't surrender. "It might have to be decided militarily; I hope this will not be the case," he said.
Burned Gadhafi family nanny gets care Gadhafi's 19-year-old female executioner 'Bad time to be a black man in Libya' Moammar Gadhafi's family photos
As fighting continued for the last bastions under Gadhafi's grip, the longtime dictator's whereabouts remained unknown to rebel authorities. A clue came from a 17-year-old boy who told Sky News he had seen Gadhafi on Friday at the compound in Tripoli belonging to one of Gadhafi's sons, Khamis. The teen said he was part of Khamis Gadhafi's group.
The leader arrived and spoke with his son for 10 to 15 minutes, said Abdu Salam Ataher-Ali, who added that he had been working for the previous month as part of Khamis Gadhafi's protection team.
Friday's visit came as the rebels were taking over the capital and Gadhafi loyalists were preparing to flee.
"He said Gadhafi was visiting us at the same time when we run away from Khamis' compound," said a translator during an interview with the teen in a rebel compound outside Tahoma. During the visit, the leader's daughter, Aisha, arrived and she and her father got into a convoy of vehicles and drove off, the teen told the translator. "He said one of the high-ranking soldiers come to us and we asked him, 'Where is Gadhafi going?' and he said to Sabha," the teen said.
Sabha is a city in southwestern Libya and one of the last remaining loyalist strongholds.
Khamis Gadhafi then got into a Toyota Land Cruiser and drove toward the town of Bani Walid, the teen said. Bani Walid is a city in the Mistrata District in the north, another Gadhafi stronghold. A Land Cruiser was among a number of vehicles that were destroyed later by NATO bombs.
But it was not clear whether Khamis died in that attack. Tripoli residents greeted the end of Ramadan with celebratory gunfire amid news of Khamis' death Sunday night after a battle with rebel forces in northwest Libya between Tarunah and Bani Walid.
A rebel commander said Khamis Gadhafi was buried in the area.
The teen said he had been persuaded to join Khamis Gadhafi's group when he was told that foreign forces were attacking the country, Sky News reported. CNN has not been able to verify the Sky News report.
Aisha and other members of Gadhafi's family, including his wife, Safia, and sons Mohamed and Hannibal, arrived Monday in neighboring Algeria.
Source: Gadhafi's daughter gives birth in Algeria
Gadhafi town falls to rebels Captives executed in Libya Sadistic brutality in Libya Lockerbie mastermind near death Fight for water in Tripoli
RELATED TOPICS
Libya
Libyan Conflict
Moammar Gadhafi
Arab Spring
Mourad Benmehidi, Algeria's ambassador to the United Nations, said his nation allowed them to enter on "humanitarian grounds."
Unlike Libya's other neighbors, Algeria has not recognized the authority of the National Transitional Council and the authoritarian government in Algiers has much to fear with Arab revolutions so close to home.
Jalil said Tuesday that the rebels would ask Algeria to extradite members of the Gadhafi family back to Libya. He also said that, once the rebels have full control of the country, courts will be set up to hear people's complaints against the Gadhafi regime.
But battles still stood in the way of total victory, most notably at Sirte and Bani Walid in the north and Sabha in the south. There has been speculation that Gadhafi could be hiding in one of those towns.
Rebel fighters forged ahead Tuesday toward Sirte, situated along the Mediterranean coast between Tripoli and the opposition nerve center of Benghazi.
Are you there? Share photos, video, but stay safe
Members of the Khamis Brigade, also known as the 32nd Brigade, were accused of human rights abuses. Human Rights Watch said Monday that the brigade executed detainees a week ago in a warehouse near Tripoli.
Forces led by Khamis Gadhafi also killed scores of captive civilians as they tried to retreat from Tripoli, according to Muneer Masoud Own, who said he survived the massacre. CNN could not independently verify the claim, though Human Rights Watch and Amnesty International both documented the alleged incident.
The United Nations has voiced "extreme alarm" at the reports of "atrocious human rights violations" in Libya, including summary executions.
"We are also deeply concerned about reports that there are still thousands of people unaccounted for who were arrested or taken prisoner by Gadhafi security forces either earlier in the conflict or before it even started," said Rupert Colville, spokesman for the U.N. High Commissioner for Human Rights.
"Given the gruesome discoveries that have taken place over the past few days, there is good reason to be extremely concerned for their safety," Colville said. "We urge any members of the former regime in a position to reveal where prisoners have been held to do so, before more lives are lost."
Burned Gadhafi family nanny being treated in Tripoli
Another report, released Tuesday by Physicians for Human Rights, documented crimes in the city of Misrata, which had been under siege from Gadhafi's forces until rebels seized control.
The report cited four witnesses who said they saw Gadhafi's troops detain 107 civilians and use them as human shields to guard munitions from NATO strikes.
One father told the physicians group that soldiers forced his two young children to sit on a tank, and threatened the family, saying, "You'll stay here, and if NATO attacks us, you'll die too."
The report, which said Gadhafi shielded weapons in markets, mosques and schools, also detailed accounts of detention and torture.
In another instance, four witnesses told the group that Gadhafi's forces demolished a home for the elderly and abducted 36 disabled and elderly people whose whereabouts remained unknown.
Signs of normalcy were visible Tuesday in Tripoli, where some shops reopened, traffic picked up and humanitarian aid was trickling in. France reopened its embassy Monday and Britain said it was preparing to do the same.
But food and water were in short supply.
The United Nations' World Food Programme was sending 600 tons of food commodities -- wheat flour, pasta, vegetable oil and tomato paste -- for the Red Cross to distribute in Tripoli.
U.N. Secretary-General Ban Ki-moon said Tuesday that 60% of Tripoli was without water or sanitation.
The U.N. children's agency was procuring 5 million liters (1.3 million gallons) of water to ship to Tripoli. The agency warned Libya was facing a potentially disastrous water shortage, mainly due to disruptions in the pipeline.
The European Union said government forces closed water pumping stations in Jebel Hassouna along the route from Tripoli to Sabha while fleeing the capital. The disruption of the water supply in Tripoli is "a major issue," an EU spokeswoman said, adding that security concerns along the road to the stations made it impossible to predict when the flow could be restored.
All 31 EU countries have been asked whether they can help if the situation worsens, she said.
Another of Gadhafi's sons, businessman Saadi Gadhafi, has offered to negotiate an end to the war with the rebels who, he said, cannot "build a new country without having us (at) the table." He has made previous offers, though this time he appeared ready to cut loose from his father and his brother Saif al-Islam, once considered the heir apparent.
"If (the rebels) agree to cooperate to save the country together, then it will be easy and fast. I promise!" Saadi Gadhafi said in an e-mail to CNN's Nic Robertson.