Bamako - Radical Islamists holed up in Mali's vast north are not a spent force despite losing two key bastions in 48 hours and could resort to guerrilla war, suicide attacks and kidnappings, experts warn.
Gao and the fabled city of Timbuktu, the two biggest urban zones in the arid region equalling Texas in size were taken by the French-led Malian forces without any resistance. It was a huge boost for the military offensive that Paris launched in its former west African colony on 11 January.
In the face of air attacks, buttressed by ground strikes, as well as devastating air bombings that destroyed their headquarters in Timbuktu as well as their fuel supplies and armoury, the Islamists had no choice but to flee the cities.
But the lack of resistance for the moment does not mean they have been neutralised, said Alain Antil, the head of sub-Saharan affairs at the French Institute of International Relations.
"They can turn to classic guerrilla tactics including harrassment, rapid attacks with kidnappings and bombings," said Antil.
The towns and cities recaptured by the French-led forces could be easy prey, he said: for apart from the main urban areas, there are no Malian troops posted along a swathe of the remote territory re-conquered.
Tuareg rebels seeking an independent homeland in Mali relaunched a rebellion in January last year in a rapid advance that led to a coup in Bamako. They soon allied with Islamists in the quest for control of the vast arid north.
The unlikely partnership between the independence-seeking Tuareg and sharia-driven Islamists quickly fell apart. The extremists took control of the region, sparking fears the zone could become a haven for terror groups.
An indication of the scale of the threat came when Islamist fighters from six countries attacked a remote gas field in Algeria, Mali's northern neighbour. They said they were protesting the French intervention against the Islamists groups in northern Mali.
'The Islamists are by no means finished'
Dozens of foreign hostages were killed in the bloody showdown with the Algerian security forces, with reports of summary executions.
Even as French forces arrived at Kidal, the last major northern town still outside their control, experts warned that recapturing the northern cities was only half the task.
"After liberating the towns, you have to manage them and keep them under your control," said Dominique Thomas from the Institute of Studies on Islam and Muslim Societies.
"That means checkpoints, that means regular controls, that also means the risk of suicide bombings and attacks."
Several reports say that the most important Islamist chiefs, Iyad Ag Ghaly from Ansar Dine (Defenders of the Faith), and the Algerian Abou Zeid from al-Qaeda in Islamic Maghreb, are gathering forces the mountainous arid region of Kidal, 1 500km northeast of the capital Bamako and near the Algerian border.
The Ifoghas mountain range near Kidal has been the area from where the Tuareg separatist movements emerged.
"They are in the process of dispersing in the north, in difficult mountainous terrain that is not easy to access or bomb," said Jean-Charles Brisard, an independent terrorism consultant.
The fighters were entering into a "new assymetrical phase of conflict in Mali and in other countries", he said.
Several Islamist groups have threatened revenge attacks against France and French interests but "for practical reasons, these groups will first think of reprisals in Africa", he said.
"Nobody is safe anymore and there are no sanctuaries. Just look at the composition of the commandos in the Algerian attack: all nationalities represented and that says everything," said Kader Abderrahim, a researcher at the Paris-based Institute of International and Strategic Relations.
The assault on the In Amenas gas field included fighters from Algeria, Tunisia, Canada, Egypt, Mali, Niger and Mauritania.
"They will regroup and re-position themselves in Libya, Algeria and Tunisia. It's above all an international network," said Souleimane Mangane, a Malian specialist on Islamist movements.
Another cause for concern is the state of Libya after the downfall of strongman Muammar Gaddafi.
"The Sahel with its porous borders" remains a cause for concern, Thomas said, stressing the need to survey "the capacity of Libya to transform into a stable and secure state".