Mali's defence minister has admitted soldiers were involved in killings in the country's troubled central region which has been plagued by violence between security forces and fighters.

The comments by Tiena Coulibaly on Tuesday came after local media reports said that 25 bodies had been found in three mass graves after a military crackdown on suspected fighters and allied ethnic militia.

The discovery of the graves added to accusations of summary executions by government troops.

"The inspection mission sent to the area confirms the existence of mass graves implicating some armed forces personnel in serious violations causing the deaths of men in Nantaka and Kobaka [Mopti region]," Tiena Coulibaly, the minister, said on Tuesday.

Coulibaly instructed military prosecutors to open an inquiry.

He said the authorities were "firmly resolved to fight impunity and get soldiers to strictly observe international rights and humanitarian conventions", a statement said.

An NGO called Kisal, which campaigns for the human rights of pastoral communities, said 25 people from the Fulani ethnic group, who are predominantly herders, were picked up last week by the army in the localities of Kobaka and Nantaka.

Human rights groups accuse the Malian military of conducting extrajudicial killings, kidnappings, torture and arbitrary arrests against suspected sympathisers of armed groups - charges the army has promised in the past to investigate.

"The announced investigation is good news, but promises aren't enough," Corinne Dufka, Human Rights Watch associate director for West Africa, told Reuters news agency.

"Since 2017, I've documented over 60 alleged executions by the army of suspects who are buried in at least seven common graves, none of which have resulted in justice for the families," added Dufka.

Mali has been in turmoil since Tuareg rebels and loosely allied armed groups took over its north in 2012, prompting French forces to intervene to push them back the following year.

Growing violence has raised doubts about whether Mali will be able to hold credible elections scheduled for the end of next month, in which President Ibrahim Boubacar Keita will seek a second term.

Al Jazeera