Al Qaeda's central leadership broke with one of its most powerful branch commanders in an apparent attempt to stem the deadly infighting that has erupted in Syria among the militant Islamic factions trying to bring down President Bashar Assad.
More broadly, the announcement on Monday (local time) appeared to be a move by al Qaeda leader Ayman al-Zawahri to reassert the terror network's prominence in the jihad movement across the Middle East amid the mushrooming of extremist groups during the upheaval of the past three years.
The dispute is between al Qaeda's central leadership and a faction known as the Islamic State of Iraq and the Levant.
Abu Bakr al-Baghdadi, the head of al Qaeda's branch in Iraq, formed the Islamic State last spring to expand his operations into neighbouring Syria, defying direct orders by al-Zawahri not to do so. Al-Zawahri named a different group, the Nusra Front, as al Qaeda's branch in Syria.
Now, the break is likely to spark a competition for resources and fighters between the two sides in what has become a civil war within a civil war. The test for al-Zawahri's influence will be whether his decision leads fighters to quit the Islamic State.
In Washington, which has viewed the increasing influence of Islamic extremism in Syria's rebel movement with unease, State Department spokesman Jen Psaki noted that both the Islamic State and the Nusra Front are considered terrorist organisations.
As for al Qaeda's attempt to distance itself from the Islamic State, she said: "There's no way for me to evaluate what it will mean in the months ahead."
In a conflict that has seen atrocities by all sides, the Islamic State has been particularly vicious.
It is believed to be dominated by thousands of non-Syrian jihadi fighters, and is seen by others in the rebellion as more concerned with venting sectarian hatreds and creating a transnational Islamic succession than with toppling Assad.
Since its creation, it has taken over swaths of territory in Syria, often imposing severe Shariah law penalties.
Its fighters have beheaded captured government fighters, carried out some of the deadliest massacres against pro-Assad minorities and kidnapped anti-Assad activists, journalists and civilians seen as critical of its rule.
It has increasingly clashed with other factions, particularly an umbrella group of Syrian rebels called the Islamic Front, which accuses it of trying to hijack the campaign to oust Assad. Even the group's name, Islamic State of Iraq and Levant, was seen as a declaration that the group was the only real Islamic movement in the country.
Those frictions erupted into outright warfare in January. Since January 3, more than 1,700 people have been killed in fighting between Islamic State and other factions, according to the London-based Syrian Observatory for Human Rights.
At the same time, al-Baghdadi has brought his group back to the forefront in his homeland Iraq. The past month, his fighters rose up and virtually took over main cities in Iraq's western Anbar province. That has made al-Baghdadi a powerful force in the jihadi movement.
With Monday's statement, al Qaeda appeared intent on undercutting al-Baghdadi's allure by making clear he was not supported by the central leadership.
Al Qaeda's general command announced it has "no connection" with the Islamic State, underlined that the group "is not a branch of the al Qaeda organisation", and said al Qaeda "is not responsible for its actions".
Al Qaeda did not condone the group's creation "and in fact ordered it to stop", the statement said. As for the infighting in Syria, al Qaeda said: "We distance ourselves from the sedition taking place among the mujahedeen factions."
The authenticity of the statement could not independently be verified, but it was posted on websites commonly used by al Qaeda.
Charles Lister of the Brookings Doha Center said the al Qaeda statement reflected its "attempt to definitively re-assert some level of authority over the jihad in Syria".
However, he said he doubts the Islamic State will back down and stop attacking rival factions.
On militant websites, Islamic State supporters lashed out at al Qaeda's leadership.
"God as my witness, al Qaeda did not do right by this mujahed group. Instead, it stood with its enemies," one supporter with the username Muslim2000 wrote.
A spokesman for the Islamic Front vowed that it will continue battling the Islamic State. Captain Islam Alloush said the Islamic State is now "without cover or co-sponsor. It has been totally stripped after al Qaeda and the people abandoned it".