Burkina Faso Army on patrol. [File, Reuters]

The death toll from a jihadi attack on a Burkina Faso army unit in the north of the country last week has risen to 51, military officials said Monday, after 43 new bodies were found.

The military unit was ambushed in the Sahel region's Oudalan province, between the towns of Deou and Oursi, the Burkinabe military said Monday. Reinforcements have been sent to the area and an unspecified number of wounded have been taken to hospital.

The West African nation has been wracked for seven years by violence linked to al-Qaida and the Islamic State group, which has killed thousands, displaced nearly 2 million people and caused a humanitarian crisis.

Successive governments' failure to effectively address the problem led to two coups last year, with each military leader vowing to stem attacks and secure the country, albeit with little success.

Last week's attack came while some 400 French special forces soldiers were leaving Burkina Faso, one month after the junta government ordered them out - following in the path of neighboring Mali, which is also ruled by a military dictatorship.

While the number of French troops in Burkina Faso was far smaller than in Mali, their departure adds to growing concerns that Islamic extremists are capitalizing on the political disarray and using it to expand their reach.

Analysts have questioned whether the countries' militaries are capable of filling the void.

"The struggle for state forces to avoid deadly attacks, especially such an ambush against convoys, is a major concern since it comes at a time where the state is trying to assert its presence and chase jihadists out from areas they control," said Rida Lyammouri, senior fellow at the Policy Center for the New South, a Moroccan-based think tank.

"If convoys are repeatedly targeted, recovering territories and providing protection for civilians is going to take a very long time and going to be deadly," Lyammouri added.