The 19-minute audiotape from Abu Bakr al-Baghdadi came two days after his organisation, the Islamic State of Iraq and the Levant, unilaterally declared the establishment of an Islamic state, or caliphate, in the land it controls.
It also proclaimed al-Baghdadi the caliph, and demanded that all Muslims around the world pledge allegiance to him.
In the statement, al-Baghdadi makes clear his global ambition and presented himself as the leader of all Muslims.
He said the Islamic state is a land for all Muslims regardless of nationality, telling them it "will return your dignity, might, rights, and leadership."
More From This Section
"It is a state where the Arab and non-Arab, the white man and black man, the easterner and westerner are all brothers," he said an appeal aimed at broadening his support base beyond the Middle East. "Muslims, rush to your state. Yes, it is your state. Rush, because Syria is not for the Syrians, and Iraq is not for the Iraqis. The earth is Allah's."
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 you righteous predecessors," he said.
"So to arms, to arms, soldiers of the Islamic state, fight, fight."
The audio was posted on militant websites where the group has issued statements in the past, and the voice resembled that on other audiotapes said to be by the shadowy al-Baghdadi, an Iraqi militant who has rarely been photographed or appeared in public.