Islamic State jihadists ambushed a Nigerian military convoy, killing 15 soldiers and four militia fighters in the northeastern state of Borno on Thursday, security sources said in a statement over the weekend.

The 10-vehicle convoy was on its way to Gudumbali from the town of Kukawa in the violent Lake Chad region to participate in a military operation against the Islamic State when it came under fire, according to military sources. 

“We lost 15 soldiers and four civilian JTF (militia) in the terrorists’ ambush in the forest near Gudumbali,” an unnamed military officer said to the AFP. He added that 13 government fighters (10 army troops, three militia) were wounded in the fighting. 

“The casualties were brought to Maiduguri (regional capital), this afternoon,” the officer added.