A convoy of vehicles carrying forces loyal to Libya's Moammar Gadhafi has crossed into neighboring Niger, as anti-Gadhafi fighters continue to amass outside one of the ousted leader's last strongholds.

A dozen military vehicles moved into Niger late Monday and arrived in the city of Agadez. It was not immediately known who the occupants in the convoy were.

Gadhafi's whereabouts are still unknown.

Meanwhile, more anti-Gadhafi reinforcements have joined thousands of fighters outside the Libyan city of Bani Walid ahead of a Saturday deadline for all loyalist holdouts to surrender.

Representatives of Libya's transitional leadership will meet with tribal leaders in Bani Walid Tuesday to reiterate that pro-Gadhafi forces will not be harmed if they peacefully surrender.

Gadhafi, his son Saif al-Islam Gadhafi and the former head of military intelligence, Abdullah Al-Senussi, face charges in the International Criminal Court at The Hague, Netherlands, for crimes against humanity related to the regime's violent crackdown against anti-government protesters.

Gadhafi's wife, three of his children and some of his grandchildren are already in Algeria. Libyan rebels are furious at Algeria for sheltering Gadhafi family members and demanded the family be sent back. But Syria had informed that it granted entrance to Gadhafi's wife, Safia, his daughter, Aisha, sons Hannibal and Muhammad and their children on humanitarian grounds.