Inside a huge U.S. military exercise in Africa to counter terrorism and Russia and China's growing influence

Tamale, Ghana — On a dusty airport tarmac in the northern Ghanaian city of Tamale, military special operatives from across Africa move stealthily. Shots ring out as they converge on the airport and apprehend armed militants holding it hostage. 

It's not a real attack, but just one of the exercises of "Flintlock," the U.S. military's premier counterterrorism training event in Africa, which is now in its 20th year.

Special ops teams from the U.S. military's Africa Command, along with NATO allies, are conducting drills alongside soldiers from countries including Ghana, Ivory Coast, Chad, Mauritania, Nigeria, Libya and Morocco.