French special forces inched closer to an al-Qaeda-held town, while fighting erupted in another community and army troops raced to protect a third, as the Islamic extremists controlling northern Mali ceded no ground Thursday, digging into the areas they already occupy and sending out scouts to widen their reach.

Banamba, a town only 144 kilometres from Mali's capital of Bamako, was put on alert overnight, and a contingent of roughly 100 Malian soldiers sped there on Thursday after a reported sighting of jihadists in the vicinity, marking the closest that the extremists have come to Mali's largest city and seat of government.

France has encountered fierce resistance from the Islamist extremist groups, whose reach extends not only over a territory the size of Afghanistan in Mali, but also as much as 1,000 kilometres east in Algeria, where fighters belonging to the cells in Mali kidnapped as many as 41 foreigners at a BP-operated plant, including Americans. They demanded the immediate end of the hostilities in Mali, with one commander, Oumar Ould Hamaha, saying that they are now "globalizing the conflict" in revenge for the military assault on Malian soil.

Map: Conflict in Mali

The first Malian troops arrived in Banamba late Wednesday, with a second group coming on Thursday. The small town northeast of Bamako is connected by a secondary road to the garrison town of Diabaly, which was taken by Islamic extremists earlier this week, and has been the scene of intense fighting with French special forces, who continued bombardments and a land assault there on Thursday.

A city official in Banamba who asked not to be named because he is not authorized to speak publicly, and who has been involved in getting the Malian troops to defend the town, said they received reports that a rebel convoy had left Diabaly on the road connecting it to Banamba.

"We don't have a [military] base here, we have no defences. So the military has come to secure the town," he said. "From Monday to today, no jihadists have entered our town. But there are reports that a column [of rebel vehicles] was seen heading toward us from Diabaly."

Civil servant Moussa Kone, the head of the government's planning, statistics, and territorial management office, said he had seen the soldiers arriving both Wednesday night and Thursday. "They have taken positions in the town, and they are out on patrol."

France has stepped up its involvement every day, after launching the first air raids last Friday in an effort to stop the rebels' advance, then only as far as the town of Konna, located 690 kilometres from the capital.

Fighting erupted anew Thursday in Konna between Islamists and Malian soldiers in the city whose capture by the militants first prompted French military intervention, while French forces kept up their bombardments of Diabaly, fleeing residents and officials said.

As refugees from Diabaly continued to flee south, authorities announced a state of alert including the closure of the largest road after sundown, fearing that the al-Qaeda-linked fighters would try to infiltrate the towns in the south.

"Starting at 6 p.m. tomorrow night, the road between Segou and Niono, the M33 highway, will be closed," said the Prefect of Niono Seydou Traore. "Neither cars, nor motorcycles, nor people on foot will be able to travel, as a security measure."

Meanwhile, France has increased its troops' strength in Mali to 1,400, said French Defence Minister Jean-Yves Le Drian.

"The actions of French forces, be it air forces or ground forces, are ongoing," said Le Drian in Paris. "They took place yesterday, they took place last night, they took place today, they will take place tomorrow."

A Nigerian Army soldier gestures during preparations for deployment to Mali on Thursday. (Afolabi Sotunde/Reuters)

After a meeting in Brussels of European Union foreign ministers, Malian Foreign Minister Tieman Hubert Coulibaly said it was necessary to mobilize "the entire international community" to help Mali and the region.

"What is happening in Mali is a global threat," Coulibaly told journalists at a news conference. "Remember what happened on Sept. 11," he said, referring to the attacks on the United States. "It is that terrorism can happen anywhere, at any moment, to anyone."

He pointed out that the hostage-taking in Algeria revealed to the world the true nature of the extremists. Islamic militants claim that at least 34 of the hostages and 15 kidnappers were killed on Thursday, after Algerian helicopters strafed the remote Sahara gas plant, located in the outpost of Ain Amenas, in far eastern Algeria, according to the Nouakchott Information Agency, which has often carried reports from al-Qaeda's groups in Africa.

France remains alone as the only foreign power with boots on the ground, but on Thursday, troops from neighbouring Nigeria are expected to begin arriving. France's ambassador to Canada, Philippe Zeller, told CBC News they would number 900 and be well-trained.

Canada committed to a C-17 military transport plane for approximately a week, and Foreign Affairs Minister John Baird left the door open to further contributions.

The plane arrived in Bamako on Thursday, after stopping in France to pick up French personnel, an armoured vehicle, 900 kilograms of batteries and other equipment. It's expected to make one delivery a day.

Zeller told CBC News Network on Thursday morning that France has asked Canada to extend its contribution of the plane beyond one week.

France controls key bridge

France is planning to deploy a total of 2,500 soldiers, more than half of what it had deployed to Afghanistan at the height of their involvement. Many of the armoured vehicles being used here were previously used in Afghanistan. On Wednesday, around 100 French Marines took over a major bridge over a large, turbulent river just north of the central administrative capital of Segou at the locality of Markala.

The river is the major separator between the southern area still firmly under government control, and the north. Any rebel convoy coming from Diabaly, located roughly 200 kilometres north of the river, would need to cross the bridge. David Bache, a freelance journalist embedded with the French marines, said that around 100 soldiers had taken positions at the bridge, setting up a camp, where they have parked 18 armoured vehicles, mounted with artillery including 90mm cannons.

Fleeing residents say that Islamic extremists have taken over their homes in Diabaly and were preventing other people from leaving. They said the fighters were melting into the population and moving only in small groups on streets in the mud-walled neighbourhoods to avoid being targeted by the French.

"They stationed themselves outside my house with a heavy weapon, I don't know what sort it was. After that came the bombing, which went on from 7:30 a.m. to 2 p.m., and after that, one of them (rebels) jumped over my garden wall to grab the keys to my car," said Thiemogo Coulibaly.

• 9 questions about the Mali conflict

In the narrow waist of central Mali, fighting reignited in the town of Konna, which the Islamists attacked last week and seized a day before French launched its military offensive. A Malian military official, who insisted on anonymity because he was not authorized to speak to journalists, said the fighting began Wednesday between Malian soldiers and Islamists from the group Ansar Dine.

Abdrahmane Guirou, a nurse, said four wounded soldiers had been brought to the local hospital.

A former French colony, Mali once enjoyed a reputation as one of West Africa's most stable democracies with the majority of its 15 million people practicing a moderate form of Islam. That changed last March, following a coup in the capital which created the disarray that allowed Islamist extremists to take over the main cities in the distant north.

Security experts warn that the extremists are carving out their own territory in northern Mali from where they can plot terror attacks in Africa and Europe. Estimates of how many fighters the Islamists have range from less than 1,000 to several thousand. The militants are well-armed and funded and include recruits from other countries.

With files from CBC News