In June 2014, it announced a worldwide caliphate. In 2014, ISIL successfully fought in a large-scale offensive in Iraq. After this offensive, ISIL is reported to have seized control of most of Mosul, the second biggest city in Iraq, its surrounding Nineveh province, and the city of Fallujah. In the spring of 2015 ISIL fought for control of Tikrit, the administrative center of the Salah ad Din Governorate.