A quiet student at Kabul University, 25-year-old Abdul Rahim has a dream: to join Islamic State in Syria and fight for the establishment of a global caliphate - a new, alarming form of radicalism in war-weary Afghanistan."When hundreds of foreigners, both men and women, leave their comfortable lives and embrace Daish, then why not us?" he asked, using a word for Islamic State common in the region.Although IS is not believed to have operations in Afghanistan, its influence is growing in a country already mired in daily bombings and attacks by Taliban insurgents.With most foreign combat troops leaving the country by the end of the year, there is growing uncertainty over what direction Afghanistan will take, with the emergence of IS ideology adding a new risk.A few dozen students have set up an underground group a few months after IS started making inroads into Central and South Asia this year.Several hardline insurgent groups in tribal areas between Afghanistan and Pakistan have pledged allegiance to IS, propaganda leaflets have been distributed and some local commanders are said to have met IS members.But the formation of the clandestine student group is the clearest indication yet that IS ideas are taking hold more broadly."Several students who are close to us went to Syria to join our brothers for a holy cause," said student Gul Rahman, holding a mobile phone with IS's black flag logo on the screen.Islamic State is a violent Sunni group which controls large areas of Iraq and Syria. It announced the establishment of a caliphate in June.IS also announced intentions to bring Afghanistan, Pakistan and India under its control, although so far only eight Afghan citizens have traveled from Afghanistan to fight in Syria, security sources told Reuters.The number is tiny compared with the thousands of recruits who have left European countries to join IS, with IS's influence in South Asia still embryonic.