The latest attack took place on Thursday evening in a village in the Bankass Circle, in Mali's Mopti region, said the mayor of the nearby town of Bankass, Moulaye Guindo.
"Unidentified armed men burst into the village and shot at people. They chased after those who fled into (surrounding) forest to kill them," Guindo told Reuters via telephone.
"This morning we counted 19 dead and the search (for bodies) is ongoing," he added.
The mayor of Kani Bonzon, another nearby town, confirmed the attack and said the local clinic had received 12 bodies so far.
"Armed men... shot at people, burnt and ransacked the village," Soumaila Guindo told Reuters. "There are many dead."
The West African nation is battling a violent insurgency with links to al Qaeda and Islamic State that took root in its arid north following a Tuareg separatist rebellion in 2012.
Mali has struggled to stem the insurgency despite the intervention of foreign troops and U.N. peacekeepers.
Militants have since spread to other countries in the Sahel region south of the Sahara and more recently to coastal states, seizing territory, killing thousands and uprooting millions in the process.