Intensifying fighting in the Central African Republic is posing a serious challenge to thousands of French and African troops struggling to restore stability in the lawless country. Paris deployed 1,600 troops to its former colony in early December with UN Security Council approval to help a 4,500-strong African force. The situation is causing deep concern in Paris. Two French soldiers have been killed to date and nine soldiers from the Republic of Congo and Chad were killed over the past month. "It is a very bad situation and it is not clear how it is going to end," says François Heisbourg, special adviser at the Foundation for Strategic Studies in Paris. The number of civilians fleeing their homes has increased sharply, aid groups and the UN have said. Tens of thousands are seeking shelter in Bangui, the capital, with more than 100,000 people camped out at the city's airport, crowding there to seek the protection of French forces securing the airfield. The situation in Bangui, where most foreign troops are based, appears "to be out of control," Médecins Sans Frontières, the medical charity, said this week. Souleymane Diabate, the head of Unicef, the UN children's agency, in the Central African Republic said the organisation was "witnessing unprecedented levels of violence," particularly against children. In the past 1,600 French soldiers was sufficient to deal with anything in the Central African Republic. That calculation was badly wrong this time François Heisbourg, Foundation for Strategic Studies in Paris Mr Hollande last month said France's short-term aim was to end the violence to allow humanitarian agencies to get food and medical aid to the population. But he added that the longer-term aim was to replace Mr Djotodia and his regime through elections intended to be held by February 2015. French officials say this remains the intention. But they acknowledge that the situation on the ground is fraught. "A climate of fear reigns in Bangui," said one. Mr Heisbourg says Paris underestimated the scale of the task, only the latest of multiple French interventions since the chronically unstable country gained independence in 1960. That calculation was badly wrong this time," he said. He said a foreign force, ideally under a European flag, of some 5,000-6,000 was needed to restore order. EU foreign ministers are due to meet on January 20 to discuss stepping up backing for the French action. French officials are seeking more logistical and financial support. Laurent Fabius, foreign minister, has talked of other European countries contributing some troops on the ground. But there seems little prospect of any significant such contribution.