sentences:  In 2005, after years of absence, the United States showed renewed military interest in the region through involvement in the "Flintlock 2005" exercise, which involved US Special Forces training soldiers from Algeria, Senegal, Mauritania, Mali, and Chad.The United States alleged that the Sahel region had become a training ground for Islamist recruits.However, the two most important pieces of evidence of 'terrorist activity' – the tourist kidnapping of 2003 and the attack on the Mauritanian army base just as "Flintlock" got underway – have subsequently been called into question.