FRENCH and Malian troops have recaptured two key towns from al-Qaeda-linked Islamists holding Mali's north, as Egypt warned the Paris-led offensive could spark regional conflict.

The inroads into the central towns of Diabaly and Douentza on Monday marked a significant advance in the 11-day offensive led by former colonial power France, whose aim is the "total reconquest" of Mali's vast semi-arid north.

But, breaking ranks with the global community - which supports the UN-backed intervention amid concerns the vast arid zone could become a new Afghanistan-like haven for al-Qaeda - Egypt was sharply critical.

"We do not accept at all the military intervention in Mali because that will fuel conflict in the region," President Mohamed Morsi said.

But in Diabaly, local residents applauded wildly as a convoy of about 30 armoured vehicles with some 200 Malian and French troops moved into the town on Monday morning.

Some shouted "Long Live France!" as the troops rolled in. Others scrambled to photograph the "liberators" on their mobile phones.

French military officials and local residents said the fleeing Islamists had riddled the town with landmines.

"There is a problem with unexploded ammunition," said Lieutenant-Colonel Frederic, in charge of the operations in Diabaly, who identified himself by his first name only in line with French army policy.

Diabaly, which lies 400 kilometres north of the capital Bamako, has been the theatre of air strikes and fighting since it was seized by Islamists a week ago.

French Defence Minister Jean-Yves Le Drian said the town of Douentza, which had been under Islamist control since September, had also been retaken by French and Malian troops.

Douentza is a strategic crossroads town some 100km east of Konna, whose capture earlier this month by extremists saw the French army swoop to the aid of the crippled and weak Malian army.

The push into the government-held southern triangle of the bow-tie shaped nation was seen as a threat to Bamako.

Amid the fighting, Mali extended by three months a state of emergency in place since January 12 and under which public gatherings, rallies and anything that can disrupt public order are banned.

"The military operations to liberate the occupied regions of our country are panning out well and the need to install a peaceful social climate throughout the country," were the reasons for extending the state of emergency, a government statement said.

Distancing themselves from Egypt's reaction, other countries offered their support - but not necessarily their soldiers - to France's intervention.

Algerian Prime Minister Abdelmalek Sellal reiterated that his country would not put boots on the ground in Mali, but stressed that the "integrity of Mali has to be preserved.

"We cannot accept a 'Sahelistan' tomorrow on the Algerian frontier," he said - a play on the word Sahel, the semi-arid belt that crosses Africa south of the Sahara desert.

German Chancellor Angela Merkel pledged support for France, saying "we cannot let them down. They are our partner", but also excluded sending soldiers for the moment.

The European Union offered to host a global meeting on Mali in Brussels on February 5, involving the African Union and the 15-nation Economic Community of West African States.

The planned deployment of around 6000 African soldiers meanwhile continued slowly into Bamako. The UN-approved African-led force is hampered by cash and logistical constraints, requiring up to 200 million euros ($A255 million).

Originally published as French, Malian troops recapture key towns