This is the Garden of the Martyrs. Attacks on ethnic Hazaras have killed so many that they have a special graveyard in Kabul.Most of those killed in a May school bombing, mainly girls, were laid to rest here. The Hazaras - a predominantly Shi'ite community - have been at the receiving end of some of the most violent attacks in Afghanistan's bloody history.Hussain Rahimi lost his sister Golsum, a 12th-grader, in that attack. Now he says he reads the Kalima - a verse that is the central tenet of Islam - every time he sets off for the mosque; in case he doesn't come back.The last two Fridays have seen suicide bombings at mosques - both claimed by Islamic State and both targeting the minority Shi'ite sect. More than 100 people were killed.Taliban authorities pledged to step up security at Shi'ite mosques last week, but few in the community have much faith in a movement long seen as their enemy. Both the Taliban and Islamic State are Sunni.Thousands of Hazaras died under the last Taliban government from 1996-2001, but it was the appearance of Islamic State in Afghanistan that made the Shi'ites a systematic target. Asif Lali, an ethnic Hazara, has decided with his family to stay away from Friday prayers for the moment. His younger brother was killed in one of the attacks."We are scared of every situation. I don't even go on the main streets, I only walk in the alleyways, because there's a fear in my mind that a suicide attack could happen. Whenever I'm stuck in a traffic jam or there are crowds of people, I fear a suicide attack, because our people are directly under threat from ISIS." The Persian-speaking Hazara are thought to trace their descent back to the armies of thirteenth century Mongol conqueror Genghis Khan. They are believed to be Afghanistan's third largest group - about 10-20% of the population.