Dozens of suspected Islamist militants attacked a Malian police base near the southern border with Ivory Coast on Wednesday, security sources said, the most southerly point in the west African country where the insurgents have struck.
Most attacks have previously been in the vast desert north, which has been in turmoil for three years, and this rare foray by the militants into the southern tip of Mali could rattle investors with mining interests in the south.
One of the security sources said about 30 gunmen waving a black flag and shouting "Allahu Akbar" ("God is greatest") had arrived on motorbikes at the base in Misseni in the Sikasso Region early on Wednesday.
A gendarme was killed in the attack and the base was burned down, the source added. A previous estimate had put the number of dead at two.
Colonel Souleymane Maiga, communication director for the Malian army, confirmed the police base in Misseni had come under attack but did not give a death toll or comment on the identity of the attackers. Reinforcements have been deployed to the area, he said.
Another army source confirmed that at least one gendarme had been killed and said several others were missing.
Ryan Cummings, chief analyst at Red 24, a risk management company, said the attack was likely to worry foreign miners who until now have had limited exposure to such risks in Mali, Africa's third largest gold producer.
The Morila gold mine, a joint venture between AngloGold Ashanti, Randgold Resources and Mali's government, lies about 150 kilometres away from Misseni.
An Islamist militant group said in May it was holding a Romanian security officer kidnapped from a manganese mine in northern Burkina Faso, which borders Mali.
The conflict in Mali erupted in 2012, when a loose coalition of separatist rebels and al-Qaida-linked militants swept across the north of the country. A French-led military intervention in 2013 drove them from the main towns they had been occupying.
United Nations and French troops have deployed to help Mali restore some order in its northern desert, which is still awash with gunmen and smugglers. Islamist militants carry out regular raids against both local and foreign troops.
The capital Bamako, which is in the south, has suffered a handful of attacks blamed on the militants, including one three months ago when gunmen opened fire on a popular restaurant, killing five people including two foreigners.
U.N. and Algerian mediators have so far failed to agree a conclusive peace deal with separatist rebels on the future of northern Mali.