Some senior Muammar Gaddafi loyalists are among a new group that has fled to Niger, according to security sources, with many others reported to have travelled on to Burkina Faso.
It comes ahead of tomorrow's deadline for the surrender of some of the deposed leader's remaining strongholds in Libya.
Gaddafi himself declared in an audio broadcast yesterday that he was still in Libya, cursing as rats and stray dogs his NATO-backed opponents who are now trying to run the large, oil-producing North African country.
Interpol has issued arrest warrants for Gaddafi, his son Saif al-Islam and intelligence chief Abdullah al-Senussi, who are all wanted by the International Criminal Court (ICC) for suspected crimes against humanity.
"Gaddafi is a fugitive whose country of nationality and the ICC want arrested and held accountable for the serious criminal charges that have been brought against him," said Ronald Noble, secretary general of the Lyons-based police organisation.
Interim Prime Minister Mahmoud Jibril, in Tripoli for the first time since Gaddafi was driven from the capital on 23 August, reminded Libyans that "the tyrant" was not yet finished.
The security sources in Niger said a party of 14 Libyans, including General Ali Kana, who commanded Gaddafi's southern troops, a second general and two other top officials had arrived in Agadez in northern Niger in a convoy of four-wheel drive vehicles yesterday afternoon.
A Reuters reporter in Agadez said the four senior officials were staying at a Gaddafi-owned hotel in the town.
Niger's government, under pressure from Western powers and Libya's new rulers to hand over former Gaddafi officials suspected of human rights abuses, has not yet commented.
It said it accepted a convoy carrying Mansour Dhao, head of Gaddafi's security brigades, on Monday on humanitarian grounds.
Libya's National Transitional Council (NTC) has given Gaddafi-held bastions such as the desert town of Bani Walid, 150km southeast of Tripoli, and the coastal city of Sirte until tomorrow to surrender or face a military assault.
There were reports of heavy fighting outside the two as forces loyal to the interim government were poised for an assault if it does not surrender.
Some NTC officials have said Gaddafi must be captured or killed before Libya can be declared liberated and a timetable for elections and a new constitution can start running.
