A member loyal to the ISIL waves an ISIL flag in Raqqa
A member loyal to the ISIL waves an ISIL flag in RaqqaReuters

Islamist militant group, ISIS, has declared that it has established a caliphate in the area stretching the northern swathe of Iraq and parts of Syria – an event that heralds a fiercer civil war in Iraq, which could force increasing presence and involvement of the United States, four years after its troops left the country.

Declaring the Islamic state, the ISIS also proclaimed the group's leader, Abu Bakr al-Baghdadi, as caliph of the area saying he would be the "leader for Muslims everywhere".

The group, less commonly known as the Islamic State in Iraq and the Levant (ISIL) and also known as ISIS, has now renamed itself as "Islamic State" while proclaiming its leader as the Caliph, Reuters reports.

The Sunni Muslim militant group has been raging war across northern Iraq and has captured key border crossings with Syria and Jordan and overrun major cities and towns. The al-Qaeda break-away group, which also has large swath of area in Syria under its stronghold, has been seeking to build the caliphate state.

In a statement posted on Islamist websites and Twitter, a group spokesman Abu Muhammad al-Adnani said their new leader "is the imam and khalifah (Caliph) for the Muslims everywhere."

The statement, which was translated into several languages and read out in an Arabic audio speech further said: "The 'Iraq and Sham' (Levant) in the name of the Islamic State is henceforth removed from all official deliberations and communications, and the official name is the Islamic State from the date of this declaration."

The group, known around the world as Jihadists, has sought to create a medieval-style caliphate extending its geographical presence in area from the Mediterranean to the Gulf.

The group calls the Shi'ite Muslims as heretics and feels they deserve death – a viewpoint that the West deems to be the breeding group for terrorism.

"It is incumbent upon all Muslims to pledge allegiance to (him) and support him...The legality of all emirates, groups, states, and organizations, becomes null by the expansion of the khalifah's authority and arrival of its troops to their areas," the statement added.

The last caliphate was dismantled nearly 100 years ago with the end of the Ottoman Empire, but with the rise of ISIS and its increasing throttlehold in the Iraqi and Syrian region in the 21st century, the International community is left with much reasons to worry about.