The African-led mission in Mali should become a UN peacekeeping operation as soon as possible, France has told the UN Security Council. French forces were deployed nearly a month ago to combat al-Qaeda-linked militants who had taken over Mali's desert northern regions. But Paris says it wants to begin pulling out its 4,000 troops in March. It wants planning for a transition to begin now so a handover can be completed in April. "From the moment that security is assured, we can envisage without changing the structures that it can be placed under the framework of UN peacekeeping operations," French Foreign Minister Laurent Fabius said. The French ambassador to the UN had raised the matter for the first time at the Security Council on Wednesday, he told reporters. France wants the UN force to help stabilise Mali and seek an end to long-standing rivalry between ethnic Tuaregs and Arabs and the rest of the population. 'Real war' Earlier, the French defence minister said troops were engaged in a "real war" with "terrorists" around the Malian town of Gao. The town is a former militant stronghold where troops are reported to have found stores of explosives and other military materials. Islamist militants were swept from Gao last month, but Jean-Yves Le Drian said clashes were continuing in the area. The Mali militants have been routed and cleared from most of the population centres. But clashes are continuing away from the towns. "When you leave the centre of captured cities, you meet jihadis left behind," Mr Le Drian told France's Europe 1 Radio. The BBC's Mamadou Moussa Ba in Gao says heavy bombardment could be heard in the centre of the city on Tuesday, with a French helicopter patrolling. He says it seems the French intervened after militants tried to launch a rocket attack on a Malian military camp. Eyewitnesses said French and African troops had left their military base in Gao on Wednesday morning and were heading towards the town of Ansongo, towards the border with Niger, our correspondent adds. Vast desert Earlier this week, French forces accompanied by hundreds of troops from Chad cleared fighters from the last rebel stronghold, the town of Kidal. Mr Le Drian also insisted that the 4,000 French troops currently deployed would be the maximum number in Mali. Islamist rebels overran towns in Mali's north, and were threatening to overthrow the government in a rapid advance last year. The crisis has since been complicated by splits in the main Islamist militant groups. There is also an overlapping rebellion by Tuareg, who want either independence or autonomy. The government is weak and unable to control the north, where tiny towns punctuate a vast desert. Officials from the UN, EU, African Union, the World Bank and dozens of nations have met in Brussels to discuss Mali's future. They are considering how elections can be held in July, as well as the financing of an international military force and humanitarian assistance.