At least 30 people, including nine soldiers, were killed in three separate incidents in Mali.
Twenty-one were killed when gunmen attacked a village in central Mali, burning houses, crops and livestock.
A group of eight soldiers also died in an ambush, while another was killed during an attack on a military camp in the Gao region.
Mali has been affected by instability since 2012, when an Islamic rebellion broke out in the north.
The village of Ogossagou, where one of Friday's attacks took place, is mainly home to the Fulani, a largely Muslim ethnic group that traditionally works as a pastor.
Other ethnic groups in Mali – including the Dogon community – accuse the Fulani of being linked to jihadist groups operating in the Sahel region.
These accusations have fueled a wave of interethnic violence in recent years.
Last March, 160 people died in another attack in Ogossagou, which authorities attributed to the Dogon militia.
The attack led to several protests against the government's perceived inaction, and Mali's prime minister at the time, Soumeylou Boubèye Maïga, later resigned.
No one took responsibility for the latest incident, but the village chief, Aly Ousmane Barry, told local media that the men attacked several hours after government troops withdrew from the area.
In a separate incident, Mali security forces said on Twitter that they had suffered "material damage" during an ambush in the village of Bintia, which killed eight soldiers.
A ninth soldier was killed in another attack on a camp in Mondoro, which is regularly targeted by militants.
Since 2012, Malian forces have managed to regain control of large areas of territory taken by militants with the help of France, which has 4,500 soldiers deployed in the region. The UN has 13,000 peacekeepers in Mali.
But thousands of lives have been lost as Mali struggles to contain the violence, which has spread to neighbors Burkina Faso and Niger.
Combating militants in the Sahel region is seen as important for keeping security further, including Europe.
French Foreign Minister Florence Parly traveled to Washington last month, hoping to convince the American to continue her logistical support – drones, intelligence and transport – which she said were crucial to the French operation.