TRIPOLI, Libya, Aug. 29 (UPI) -- The wife of Libyan strongman Moammar Gadhafi and three of his children are in Algeria, Algerian officials say, fueling speculation he also has fled Libya.
The Algerian Press Service reported Gadhafi's wife Safia, daughter Aisha and sons Mohamed and Hannibal, and their children, crossed the border in a Mercedes and a bus early Monday to flee the advancing rebels in Libya.
Mourad Benmehidi, the Algerian permanent representative to the United Nations, confirmed Algeria had allowed them to enter on humanitarian grounds, The New York Times reported. Gadhafi, however, was not part of the group, Benmehidi said.
Gadhafi's whereabouts have been a mystery since rebels overran his Tripoli compound last week. Gadhafi and another son, Saif al-Islam, are the subject of warrants from the International Criminal Court in The Hague and the whereabouts of two other sons, Mutassim and Saadi, also were unclear.
The Times, quoting an unidentified Algerian Foreign Ministry official, said the family had gone to Algiers.
The report came as fighting continued in Sirte, Gadhafi's hometown, and rebels called for continued NATO air support.
Libyan rebel leaders said they're worried about what has happened to tens of thousands of prisoners held in Tripoli by Gadhafi's regime.
Col. Ahmed Omar Bani, a rebel military spokesman, said nearly 50,000 prisoners arrested in recent months remain unaccounted-for, the BBC reported.
Although human rights groups reported seeing evidence of people having been massacred near prisons, Bani did not accuse anyone of killing the prisoners.
"The number of people arrested over the past months is estimated at between 57,000 and 60,000," he said in a news conference in Benghazi. "Between 10,000 and 11,000 prisoners have been freed up until now ... so where are the others?"
A mass grave and several dozen charred corpses were found south of the capital in the past few days in an area considered pro-Gadhafi that has had fierce fighting, the Tripoli Post reported.
"It is high time those who claimed to have been too frightened to speak to come forward and testify about the crimes [that] were being committed or they will be considered complicit in these crimes," Bani said.
Mustafa Abdul Jalil, head of the rebels' National Transitional Council, has said people who worked for Gadhafi would receive fair trials.
He said the reward for killing or capturing the fallen leader could be increased. Last week, a reward reported as either $1.4 million or $1.7 million was offered for Gadhafi's capture, dead or alive.
Rebel forces stormed Tripoli last week and took control of nearly all of the city after two days of fighting.
Gadhafi forces still battled rebels elsewhere in Libya, especially in his hometown of Sirte. Rebel commanders said Gadhafi's forces were using civilians as human shields, the British newspaper The Guardian reported.
During the weekend, a representative of Gadhafi's regime offered to open talks with the rebel government, which rejected the offer, the Los Angeles Times reported.
"We have no negotiations with Gadhafi and we can offer him only two things: safety and a fair trial," said Ahmad Darrat, reportedly the incoming interior minister.
"There's no negotiations," Mahmoud Shammam, an NTC spokesman in Tripoli said. "There were no negotiations before. There are criminals running from justice. We're not talking to him. We're going to arrest him."
At a meeting of defense ministers in Doha, Qatar, Jalil said Gadhafi was a threat to Libya and the world.
"I call for continued protection from NATO and its allies from this tyrant," Jalil said. "He is still a threat, not just for Libyans but for the entire world."
U.S. Adm. Samuel Locklear, commander of the NATO Joint Operations Command, said in Doha the alliance's mission in Libya would continue until at least Sept. 27, when its mandate expires.
"We believe the Gadhafi regime is near collapse and we're committed to seeing the operation through to its conclusion," Locklear said. "Pockets of pro-Gadhafi forces are being reduced day by day. The regime no longer has the capacity to mount a decisive operation."