The so-called ’Islamic State of Iraq and the Levant (ISIL) terrorist group committing massacres across Syria and Iraq – have proclaimed the establishment of a “caliphate”.

The so-called 'Islamic State of Iraq and the Levant (ISIL) terrorist group committing massacres across Syria and Iraq – have proclaimed the establishment of a “caliphate”.

Now calling itself the Islamic State, the terrorist group has called on all other related armed extremist factions, including al-Qaeda, to pledge their allegiance to the new state, which it said stretches from Aleppo in Syria to Diyala in Iraq.

In a statement distributed online on Sunday – the self-proclaimed 'Islamic State' declared its chief Abu Bakr al-Baghdadi as "the caliph" and "leader for Muslims everywhere". Baghdadi is thought to be the leader behind ISIL.

The group’s statement – translated from Arabic into English, French, Russian and German – made it clear it would perceive any group that failed to pledge allegiance an enemy.

“The infidels are disgraced. The Sunnis are masters and are esteemed. The people of heresy are humiliated. The Sharia penalties are implemented, all of them, the statement read.

“The front lines are defended, crosses and graves demolished. Governors and judges have been appointed, a tax has been enforced and courts will resolve disputes and complaints,” it added.

Baghdadi took over the group in 2010. Back then ISI, as it was known, was aligned to al-Qaeda and in a weakened state following a surge of US forces deployed to Iraq and the coalition of tribal groups that fought against al-Qaeda’s presence in the country.

Relations between ISIL and its prior incarnations and al-Qaeda have been fraught with distrust, open competition, and outright hostility, said Aaron Zelin, a fellow at the Washington Institute for Near East Policy, describing the two groups as “now in an open war for supremacy of the global jihadist movement”.

Meanwhile, a fierce battle raged in the northern Iraqi city of Tikrit after the Iraqi military launched an offensive to try to take back Tikrit from armed groups after they lost control of the area on June 11.