Bamako - A UN helicopter crashed in northern Mali on Wednesday in an apparent accident while serving with the 12 000-strong peacekeeping force in the country, a UN source told AFP."One of our helicopters crashed in northern Mali today... This was an accident. We will release the toll later," the source in the northern city of Gao said.The UN source added that "nothing at this stage" would suggest the aircraft "was hit or shot at". Northern Mali is the site of frequent fighting between armed groups, as well as a haven for jihadist activity.The United Nations force, known as MINUSMA, is considered the UN's most dangerous peacekeeping mission.In 2012, Mali's north fell under the control of jihadist groups linked to Al-Qaeda who exploited an ethnic Tuareg-led rebel uprising.While the Islamists were largely ousted by a French-led military operation, attacks have continued on civilians, the Malian army as well as on UN and French forces.Previously two Dutch UN peacekeepers died in 2015 when their Apache attack helicopter crashed in northern Mali.