The Sahel-based branch of al-Qaida, Jama’at Nusrat al-Islam wal Muslimeen (JNIM), has claimed an attack on a convoy in Burkina Faso that killed more than a dozen soldiers last month, the SITE Intelligence Group said Tuesday.

Islamist militants attacked a convoy taking supplies to a town in northern Burkina Faso on September 26, days before the West African country was hit by its second military takeover this year.

JNIM claimed credit for the ambush and said it “caused significant economic losses to the enemy and ‘led to a shakeup’ in the Burkinabe army ranks, culminating in the military coup,” the SITE statement said.

Eleven soldiers were found dead and about 50 civilians were reported missing after the attack, the previous government said.

But an internal security document seen by Reuters on Tuesday gave a death toll of 27 soldiers.