The leader of the extremist group that seized much of northern Iraq and Syria called on Muslims worldwide on Tuesday to join the battle and help build an Islamic state in the newly conquered territory.

The 19-minute audiotape from Abu Bakr al-Baghdadi came two days after his organization, 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. With his group's dramatic blitz in the heart of the Middle East, the Iraqi-born al-Baghdadi has made a bid to eclipse even al-Qaeda chief Ayman al-Zawahri as the jihadi movement's most influential figure.

'Rush to your state'

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."

"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."

To help build that state, he appealed to those with practical skills — scholars, judges, doctors, engineers and people with military and administrative expertise — to come "answer the dire need of the Muslims for them."

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."

Al-Baghdadi also urged Muslims worldwide to "Stand up and rise. For the time has come for you to free yourself from the shackles of weakness, and stand in the face of tyranny."

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.

Magnet for jihadi fighters

Al-Baghdadi's group has already been a magnet for jihadi fighters from across the Arab world, the Caucasus and extremists from Europe and some from the United States — drawn by an organization that in a few short years has transformed from just an al-Qaeda affiliate in Iraq into a transnational military force that has conquered and held a massive chunk of territory. al-Qaeda's al-Zawahri ejected al-Baghdadi from the terror network earlier this year.

Over the past year alone, al-Baghdadi's group — which has changed its name to simply the Islamic State, dropping the reference to Iraq and the Levant — has managed to effectively erase the Syria-Iraq border and lay the foundations of its proto-state. In June, Iraq saw its deadliest month in years, with more than 2,400 people killed, a reflection of the havoc wreaked as the group's fighters captured the country's second largest city in the north, Mosul, then swept south seizing most Sunni-dominated areas of northern and western Iraq and pushing close to Baghdad.

The Sunni insurgents' advance in Iraq appears to have crested, at least for now, as it reaches Shia-majority areas, where resistance is tougher, and as it seeks to consolidate its control of the territory already in hand.