Members of Moammar Gadhafi's family have entered Algeria, Algeria's state news agency said Monday, but the whereabouts of the ousted Libyan leader were unknown. Libyan rebels claimed to have killed one of his sons.

The report by APS news agency cited Algeria's Foreign Affairs Ministry as saying Gadhafi's wife Safia, his sons Mohammed and Hannibal, and his daughter Aisha entered the neighboring country on Monday. It did not immediately provide additional details or say whether Gadhafi himself was with the family.

The Egyptian news agency MENA, quoting unidentified rebel fighters, had reported from Tripoli over the weekend that six armored Mercedes sedans, possibly carrying Gadhafi's sons or other top regime figures, had crossed the border at the southwestern Libyan town of Ghadamis into Algeria. Algeria's Foreign Ministry had denied that report.

Libya's de facto government said it considers Algeria's apparent sheltering of members of Gadhafi's family an act of aggression and will seek their extradition.

"We have promised to provide a just trial to all those criminals and therefore we consider this an act of aggression,'' Mahmoud Shamman, a National Transitional Council spokesman, told Reuters.

"We are warning anybody not to shelter Gadhafi and his sons. We are going after them in any place to find them and arrest them,'' he said.

Meanwhile, Libyan rebels commanders said another of Gadhafi's son, Khamis Gadhafi, was killed in an airstrike about 60 km (37 miles) south of Tripoli, Britain's Sky News reported.

Khamis was said to have been in an armored four-wheel-drive vehicle that was struck by a missile apparently fired from a NATO Apache helicopter, Sky News said.

Sky News' chief correspondent Stuart Ramsay, who was at the scene, said a man claiming to be Khamis' bodyguard confirmed that Khamis had died in the vehicle.

Col. Al-Mahdi Al-Haragi, in charge of the Tripoli Brigade of the rebel army, said he had confirmation that Khamis was badly wounded in the clash near Ben Walid and Tarhoni. He was taken to a hospital but died of his wounds and was buried in the area, Al-Haragi said, without giving the timing.

A U.S. official, speaking on condition of anonymity, told Reuters the U.S. could not yet independently confirm Khamis' death but said similar information was being received in Washington from "reliable sources."

Earlier on Monday, prosecutor Luis Moreno-Ocampo of the International Criminal Court told Reuters he may apply for an arrest warrant for Khamis.

Human Rights Watch said members of the Khamis Brigade, a force commanded by him, appeared to have carried out summary executions of detainees whose bodies were found in a warehouse in Tripoli.

The Hague-based ICC has already approved warrants for the arrest of Moammar Gadhafi, his son Seif al-Islam, and Libyan intelligence chief Abdullah al-Senoussi on charges of crimes against humanity.

The developments came as rebel forces were converging on Gadhafi's hometown of Sirte, hoping to deliver the coup de grace of their revolution.

The fugitive Gadhafi's whereabouts were still not known and it was possible he was still in hiding in Tripoli after it fell to rebel forces and his 42-year-old reign collapsed.

The U.S. has seen no indication that Gadhafi has left Libya, the White House said on Monday.

"If we knew where he was, we would pass that on to the opposition forces,'' White House spokesman Jay Carney told reporters.

There was some fighting Monday on the eastern and western approaches to Sirte. Some have speculated that Gadhafi and other senior regime figures may have fled there.

A NATO officer, who asked not to be identified because of alliance rules, said there was fighting 30 miles (50 kilometers) east of Sirte. He said there are still clashes around Sirte, Bani Walid south of Misrata and Sebha further south.

Taking Sirte will mean getting past entrances that are reportedly mined and an elite military unit. Gadhafi's tribe is the most powerful in the city. Libyans familiar with the coastal city on which Gadhafi has lavished building projects say its first line of defense is a heavily fortified area called the al-Wadi al-Ahmar, 55 miles (90 kilometers) to the east.

The rebels asked NATO Monday to keep up pressure on remnants of Gadhafi's regime.

"Even after the fighting ends, we still need logistical and military support from NATO," Abdul-Jalil said in Qatar. NATO has been bombing Gadhafi's forces since March under a United Nations mandate to protect Libyan civilians.

In other developments, the chairman of the African Union on Monday accused Libyan rebels of indiscriminately killing black people because they have confused innocent migrant workers with Gadhafi's mercenaries. Jean Ping, speaking to reporters in Ethiopia, added this is one of the reasons the AU is refusing to recognize the National Transitional Council as Libya's interim government.

Ping's charges are much stronger than any that have been levied at the rebels by international rights groups. The groups have, however, expressed concern about beatings and detentions of immigrants from sub-Saharan Africa.

Gadhafi had recruited fighters from further south on the continent, but many sub-Saharan Africans are in the country as laborers.

National Transitional Council spokesman Abdel-Hafiz Ghoga denied the AU claims.

"These allegations have been made during the early days of the revolution. This never took place."

Source:msnbc.msn