The U.S. military is launching its annual training exercise with armies from across Africa this week in Chad, as the countries of the region battle a growing threat from the Nigerian Islamic extremist group Boko Haram.

Some 1,300 participants from 28 countries are joining in the Flintlock exercise that lasts until March 9. It includes counter-terrorism forces not only from the U.S. but from other Western countries and a number of African militaries including several of the armies who have pledged to support Nigeria in its battle against the jihadists.

The annual exercise first began in 2006 in part to counter the rise of al-Qaida-linked militants in the Sahel region. Now the most imminent danger to regional security is Boko Haram, which killed at least 10,000 people in Nigeria last year and is now staging cross-border attacks in Cameroon, Niger and Chad.

"We must respond to this immense security challenge, which is a major concern. You will agree that this is a difficult task, because terrorism has no face and no jurisdiction," Chadian Gen. Brahim Seid Mahamat said at an opening ceremony Monday, according to comments published by the U.S. military.

Col. George Thiebes, commander of special operations with Command Forward-West Africa, which leads the Flintlock exercise, said one of the challenges is helping armies from different countries to work together. While the upcoming multinational force against Boko Haram is not a specific focus of Flintlock, the training is aimed at broader themes that will apply to that mission.

"We look at how we can get the nations to work together against a common threat," Thiebes told The Associated Press.

Among the obstacles: Disparate radio systems, harsh terrain and finding common vocabulary even when troops speak the same language, he said.

Chad is the host country, though other planned stations are Niger, Nigeria, Cameroon and Tunisia. Thiebes said the training is going ahead despite a recent series of Boko Haram attacks on Niger and Cameroon.

___

Online: http://www.africom.mil/what-we-do/exercises/flintlock