BAGHDAD — The extremist group battling its way through swaths of Iraq and Syria declared the creation of a formal Islamic state Sunday, building on its recent military gains and laying down an ambitious challenge to al-Qaida's established leadership.
In an audio statement posted on the Internet, the spokesman for the Islamic State of Iraq and Syria announced the restoration of the 7th-century Islamic caliphate, a long-declared goal of al-Qaida renegades who broke with the mainstream organization early this year and have since asserted control over large areas spanning the two countries.
The move signifies "a new era of international jihad," said the spokesman, Abu Mohammed al-Adnani, who also declared an end to ISIS, as the group had called itself. Henceforth, ISIS will simply be known as the Islamic State, in recognition of the breakdown of international borders achieved as a result of the group's conquests, he said. ISIS's chief, an Iraqi known as Abu Bakr al-Baghdadi, will be the caliph, or leader, of the new caliphate, and all Muslims worldwide will be required to pay allegiance to him.
The proclamation is a powerful challenge to al-Qaida's chief, Ayman al-Zawahiri, who also claims supremacy over the global jihadist movement. Al-Zawahiri repudiated al-Baghdadi early this year after the Iraqi leader rejected repeated al-Qaida directives to adopt a more inclusive approach toward other jihadist groups, and it is unlikely that al-Zawahiri will agree to bow to the authority of the proclaimed new caliph.
"This is a threat to the legitimacy of al-Qaida as the representative of global jihad, and it lays down the threat big time," said Charles Lister of the Brookings Doha Center in Qatar. "Put simply, Abu Bakr al-Baghdadi has declared war on al-Qaida."
The state will cover lands now under Islamic State control, stretching from the northern Syrian province of Aleppo to the eastern Iraqi province of Diyala, the statement said, adding that eventually it will grow to include the entire Muslim world.
The militants have already asserted a de facto Islamic state in those areas, establishing their own courts, schools and services. The effort has received a big boost in the past three weeks from the vast quantities of weaponry the militants have taken from Iraqi army bases and the millions of dollars they have seized from banks in the towns and cities they have overrun.
On Sunday, the militants said they had repelled an Iraqi government counteroffensive against the city of Tikrit, which fell under the control of the militants more than two weeks ago.
Residents said the insurgents, who have been assisted by local antigovernment groups, were still in control of the town center, despite state TV claims that the government had cleared Tikrit of militants Saturday.
Government forces pounded the city Sunday with helicopter fire and artillery, residents said.
The government received a boost in its battle with the militants with the arrival in Baghdad late Saturday of five Sukhoi 25 warplanes purchased secondhand from Russia. The aircraft is designed to provide close air support to ground forces and to destroy mobile targets.
Information from the Associated Press was used in this report.