The attack deals another blow to the West African country's military, which is still reeling from deadly raids in late September in which 38 soldiers were killed.
The number of soldiers killed on Friday in a "terrorist attack" on a Mali military post in the northeast of the country has jumped to 53, the government said.
"Following an attack on a FAMA (the Malian armed forces) position in Indelimane, reinforcements have found 54 bodies, one of which was a civilian," the country's communication minister Yaya Sangare said on Twitter.
The attack deals another blow to the West African country's military, which is still reeling from deadly raids in late September that underscored the increasing reach and sophistication of armed groups operating in the region.
From their stronghold in Mali, groups with Al Qaeda and Daesh links have been able to fan out across the Sahel, destabilising parts of Niger and Burkina Faso.
Thirty-eight Malian soldiers were killed on September 30 in coordinated attacks on two army bases in central Mali, which has slipped from government control despite the presence of the French army and other international forces.