"Rush, O Muslims to your state. It is your state. Syria is not for Syrians and Iraq is not for Iraqis. The land is for the Muslims, all Muslims. This is my advice to you. If you hold to it you will conquer Rome and own the world, if Allah wills."

Militants from an al-Qaeda splinter group held a military parade in their stronghold in northeastern Syria, displaying US-made Humvees, heavy machine guns, and missiles captured from the Iraqi army. Credit:AP

The speech came hours after Iraq's parliament failed to appoint a new leadership amid divisions between Shiite, Sunni and Kurdish MPs. Iraq must vote on a president, prime minister and speaker in the wake of recent elections.

Having claimed the title of "caliph", Baghdadi appealed to "judges and those who have military and managerial and service skills, and doctors and engineers in all fields." He also called on jihadi fighters to escalate fighting in the holy month of Ramadan, which began on Sunday. "In this virtuous month or in any other month, there is no deed better than jihad in the path of Allah, so take advantage of this opportunity and walk the path of your righteous predecessors," he said.

In a reflection of the havoc wreaked the past month by the Sunni insurgency led by the group, the United Nations said that more than 2,400 people were killed in Iraq in June, making it the deadliest month in the country in years.