The correct answer is - Talibans.
The Talibans were initially young man that were trained, sponsored, and armed by the USA and Saudi Arabia in order to fight against the Soviet Union's army that was invading Afghanistan.
As the Soviets got out of the country, the Talibans remained there. These young man were thought strictly by the Islam ways, to implement and respect only the Sharia law, and they had ambitions to take over the whole country, creating further an Islamic Caliphate. Also, they ended up with huge amounts of weapons in their hands that was given to them by USA and Saudi Arabia who never took it back.
Eventually that led to the Talibans becoming a strong terrorist organization, controlling at one point three quarters of the Afghan territory, and killing thousands of innocent people and performing terrorist attack as their daily routine.