At least 30 soldiers were killed at the Boulkessi army base in central Mali on Sunday in an attack claimed by the Al-Qaeda affiliated Group for the Support of Islam and Muslims (JNIM).

On Friday, a religious holiday in Mali, soldiers left the post after a new deadly assault, locals and a military source said, affirming there had been multiple deaths in a Thursday attack.

"We are worried here in Boulkessi, very worried," a civil servant told AFP.

"The soldiers have abandoned the Boulkessi camp. They left with all their belongings. The camp was attacked again yesterday," the person said.

Mali marked the Muslim festival of Eid el-Adha, known locally as Tabaski, Friday.

"Today after the holiday prayer, we noticed that the last Malian soldiers who were in the Boulkessi camp had left, they had abandoned the camp," a local elected official told AFP.

Describing the departure as coming "at the request of the hierarchy", one security source told AFP the move was "strategic", contrary "to what Mali's enemies say".

Another miliary source called it "purely tactical".

While officials reported at least 30 dead in the first attack at Boulkessi Sunday, JNIM alleged it had killed more than 100 personnel and taken another 22 prisoner, on its Al-Zallaqa Foundation media platform.

That statement was verified Saturday by SITE, a US organisation that follows radicalised groups.

Attackers carried out an additional assault Monday on an army base and airport in the storied northern city of Timbuktu.

Then on Thursday, insurgents attacked an army post in the village of Mahou in the southeastern Sikasso region, killing five.

The army's general staff acknowledged the uptick in violence in a statement Thursday that said recent weeks had been marked by a "resurgence of cowardly and barbaric attacks against localities, peaceful populations, as well as military bases".

It added that "these acts are being committed by a coalition of armed terrorist groups of all persuasions with internal and external support".

Authorities have implemented or extended curfews in multiple locations across the country, notably the Timbuktu, Sikasso, Segou and Dioila regions.

Junta-ruled Mali has since 2012 faced attacks from groups linked to Al-Qaeda and the Islamic State group as well as separatist movements and criminal gangs.