The fighting on Tuesday between the towns of Mopti and Segou also left seven jihadists dead, the army said overnight, giving an earlier toll of three killed and five wounded.
The clashes occurred after the security forces came under attack from several improvised explosive devices (IEDs), the army said in its statement, published on social media.
An army officer in Segou, speaking on condition of anonymity, told an AFP reporter, "the toll from the ambush yesterday (was) 13 dead.
"This morning, a seriously wounded (soldier) died from his injuries, which makes 14 dead, including a captain who was commanding the escort," the officer said.
A local gendarmerie officer, also asking not to be identified, said the unit's commander "and all his team died in the ambush. We have lost more than 12 men."
He also said 30 soldiers were wounded and others were listed missing, while more than 30 jihadists had been killed.
Mali is in the throes of a nearly 11-year-old security crisis triggered by a regional revolt in the north that developed into a full-blown jihadist insurgency.
Thousands have died, hundreds of thousands have fled their homes and devastating economic damage has been inflicted to one of the world's poorest countries.
In 2015, the insurgency spread to neighbouring Niger and Burkina Faso.
Since August 2020, Mali has been ruled by the military, leading to a bustup with France, the country's traditional ally, and close ties with Russia.
A UN report presented to the Security Council on Tuesday said the security situation has "continued to deteriorate in (the) central Sahel, notably in Burkina Faso and Mali."
"In Mali, following the departure of international forces, armed groups have advanced in the east, gaining control of large areas bordering the Niger," the report said.