Washington: Visiting Afghan President Ashraf Ghani has warned that extremist groups such as Islamic State (IS) pose a "grave and present danger" to Afghanistan's security transition.

"Afghanistan's security transition took place against the backdrop of the unexpected rise of religious extremism in the Middle East," Ghani on Wednesday told a joint session of US Congress. " Terrorist movements whose goal is to destabilise every state in the region are looking for new bases of operation. We are the front line, Xinhua reported".