The spokesman for the Islamic State of Iraq and the Levant, Abu Mohammed al-Adnani, made the announcement in an audio statement posted online. Islamic extremists have long dreamed of recreating the Islamic state, or caliphate, that ruled over the Middle East for hundreds of years.
Abu Mohammed al-Adnani said the group's chief, Abu Bakr al-Baghdadi, is the new leader, or caliph, of the Islamic state. He called on those living in the areas under the organisation's control to swear allegiance to al-Baghdadi and support him.
"The legality of all emirates, groups, states and organisations becomes null by the expansion of the caliph's authority and the arrival of its troops to their areas," al-Adnani said.
He said that with the creation of the caliphate, the group was changing its name to just the Islamic State, dropping the mention of Iraq and the Levant.
It was unclear what immediate practical impact the declaration would have on the ground in Syria and Iraq, or among the wider global jihadi community.