Map locating the rebel-held territory in northern Mali and the town of Konna.

United Nations -

An estimated 30 000 people may have been displaced by fighting in central and northern Mali since Islamist insurgents suddenly started moving south last week, the United Nations said on Monday.

UN deputy spokesman Eduardo del Bueys said it's feared the number may be higher because some rebel groups are reportedly preventing Malians from fleeing to the government-controlled south.

Del Buey told reporters that a total of 230 000 people have been displaced by fighting and insecurity in Mali since March 2012, when the democratically elected president was overthrown by mutinous soldiers in a coup, creating a security vacuum.

That led secular Tuaregs, who have long felt marginalised by Mali's government, to take half the north as a new homeland but months later they were kicked out by Islamist groups allied with al-Qaeda, who took control of the north and have imposed strict Shariah law.

Late in 2012, the 15-nation in West African regional group known as ECOWAS, which includes Mali, agreed on a proposal for the military to take back the north, and sought backing from the United Nations. The Security Council in December authorised an African-led force to support Malian forces in recovering the north - an area the size of Texas - but gave no timeline for military action, setting benchmarks instead for a political settlement.

The Islamists unexpectedly started heading south last week and on Thursday captured the city of Konna, which the weak Malian army was unable to hold. The Islamists appeared headed to the nearby city of Mopti, which has 100 000 inhabitants, and the capital, Bamako.

Mali's president asked France for help on Thursday and a day later French troops launched a military offensive against the rebels. The Islamist fighters responded to French airstrikes and military action with a counter-offensive Monday, overrunning the garrison town of Diabaly.

France's UN Ambassador Gerard Araud told reporters that the government had sought a political solution for the last 12 months but felt it had no choice but to intervene when the Islamists took Konna.

“Our assessment was that they were totally able to take Bamako - and so we decided that what was at stake was the existence of the state of Mali, and beyond Mali was the stability of all West Africa,” he said after a closed briefing to the Security Council Monday by the UN political chief. “So it's with determination, but also with reluctance, that we have decided that we had no other choice that to launch this military intervention. And we'll conduct it as long as it will be necessary.”

He said the Malian army “have suffered heavy casualties but they are fighting - they are fighting in very difficult circumstances.”

Araud said African forces are going to be deployed to Mali in the coming days and weeks, and the Nigerian who will head the force is already in Bamako.

One of the benchmarks set by the Security Council was to train the African and Malian force before it deploys to retake the north.

“I don't see sending these contingents to the fire before first having assessed the military capabilities adequately” and melding the units into a force, Araud said.

He said France has received offers of logistical help from the United States, Canada, Britain, Denmark, Belgium, and “maybe Germany.”

Del Buey said UN Secretary-General Ban Ki-moon welcomes the response to Mali's call for assistance, and “hopes these actions will help to arrest the latest offensive.”

He said Ban spoke on Saturday to Ivory Coast President and ECOWAS Chair Alassane Ouattara, who briefed him on the upcoming ECOWAS summit in Nigeria on January 19, and plans by several members to deploy military forces to Mali. He also spoke to French Foreign Minister Laurent Fabius.

Del Buey said the Mauritanian Ministry of Interior has confirmed that thousands of refugees are on their way from Mali to the border with Mauritania. But he said significant number of refugees have not been seen arriving in Mali's other neighbours, Burkina Faso and Niger.

The UN World Food Program reported Monday that the conflict in northern Mali has triggered wide displacement within the country and into neighbouring countries, “uprooting half a million people and placing pressure on vulnerable host communities still recovering from the Sahel drought,” del Buey said.

While insecurity is severely limiting the food agency's access to northern Mali, he said WFP has managed to get emergency food to 270 000 people through its partners, including 70 000 people who are internally displaced.