Updated

Deep in the desert a loud explosion blows the roof off a Chevy Suburban, scattering car parts amid flames and black smoke.

Earlier, a Mercedes Benz was blown up, its doors flying open.

The recent explosions mimicked attacks by Islamic extremists, and are part of U.S.-led training of West African forces aimed at improving intelligence-gathering, cross-border communication and coordination between military forces and first responders.

The emphasis on explosives comes as extremist groups in the region are increasingly using them and their attacks are becoming more sophisticated. In Mali earlier this month, Islamic extremists detonated explosives that killed seven peacekeepers and wounded 30 at a U.N. base in the northern city of Kidal. Boko Haram, the Nigerian extremist group, recently killed two Cameroonian soldiers with a land mine. Earlier, Cameroonian forces dismantled Boko Haram bomb factories in Goshi, Nigeria.

The recent training witnessed by an Associated Press reporter for 50 Senegalese police, gendarmes, customs and judicial officials is part of the annual U.S.-led Flintlock exercises, a more than decade-old effort to help Africans counter threats from extremist militants. Held in Senegal and Mauritania this year, the training for the first time included African law enforcement officials.

"It's important to collaborate, share intelligence and work together because we all may have one little piece of the puzzle," said Victor Lloyd, legal attache at the U.S. Embassy in Dakar. "And the reality of it is the terrorists only have to get it right once. We have to get it right every single time."

Senegalese civilian law enforcement agents learned from the Federal Bureau of Investigation, the U.S. Bureau of Diplomatic Security and the Office of Anti-Terrorism Assistance about detecting explosives and intelligence- and evidence-gathering at blast scenes, investigative techniques that can identify the signatures of different groups. Mauritanian officers have also been brought into various exercises.

After the blast that blew up the Mercedes last week, Senegalese training participants roped off an area around the vehicle with yellow caution tape, taking photos and walking in tight lines to survey debris as FBI trainers guided them through the exercise.

In the coming days, identification found on two mannequins in the vehicles will show they came from Mauritania, and fragments and the location of the blast will indicate it was a suicide vest detonated too early. The Senegalese officials are then expected to contact gendarmes in Mauritania, whose cooperation will result a few days later in a simulated raid.

Dione Rokhayatou, a member of a four-person section of the Dakar prosecutor's office that handles extremist cases, said the training has been valuable.

"This gives us a better understanding of the work done by investigators looking into acts of terrorism, and what is needed," she said.

Senegal hasn't been hit by the kind of attacks that have rocked Burkina Faso and Mali in recent months, but officials are aware that all of West Africa is under threat.

"Although nothing has happened in Senegal, the threat exists," said Maj. Issa Diack, commander of investigations for Senegal's gendarmerie. "This (training) gives us the means to react."

In all, more than 1,700 military and law enforcement personnel from about 30 countries are participating in the month-long Flintlock exercise.