Factbox-What is Islamic State, the group claiming responsibility for Pakistan attack?

By Michael GeorgyFeb 6 (Reuters) - Islamic State on Friday claimed responsibility for an attack by a suicide bomber on a Shi'ite Muslim mosque in Islamabad that killed at least 31 people.It was the deadliest attack of its kind in Pakistan's capital in more than a decade.Here are some more details on the group.WHAT IS ISLAMIC STATE?The Sunni Muslim group emerged in Iraq and Syria and quickly created a "caliphate", declaring its rule over all Muslims and largely displacing al Qaeda.