(Iraqi refugees, who fled from the violence in Mosul, walk during sunset inside the Khazer refugee camp on the outskirts of Arbil, in Iraq's Kurdistan region, June 27, 2014. Grand Ayatollah Ali Sistani, the most influential Shi'ite cleric in Iraq, called on the country's leaders on Friday to choose a prime minister within the next four days, a dramatic political intervention that could hasten the end of Nuri al-Maliki's eight year rule. REUTERS/Ahmed Jadallah )

(Iraqi refugees, who fled from the violence in Mosul, walk during sunset inside the Khazer refugee camp on the outskirts of Arbil, in Iraq’s Kurdistan region, June 27, 2014. REUTERS/Ahmed Jadallah )