an estimated 15% of citizens in saudi arabia are shia muslims, most of whom are adherents to twelver shia islam. twelvers are predominantly represented by the baharna community living in the eastern province, with the largest concentrations in qatif, al-hasa, and dammam. in addition there is a small twelver shia minority in medina (called the nakhawila). sizable zaydi and isma'ili communities also live in najran along the border with yemen.