NEW YORK — Al Qaeda’s top leadership moved publicly on Monday to sever the organization’s relationship with its Syrian affiliate, which has been widely blamed in recent months for stoking rebel infighting in Syria’s civil war.
In a statement distributed on jihadist websites, the Al Qaeda leadership said it no longer had any connection with the affiliate, the Islamic State of Iraq and the Levant, which has asserted an increasingly important role in the Syrian conflict and stoked the enmity of other groups fighting to topple the government of President Bashar Assad.
Although the authenticity of the statement could not be confirmed, the SITE Intelligence Group, an organization that tracks jihadist communications on the Internet, posted a summary of the statement on its website, suggesting it was credible.
The motivation for breaking the relationship appeared to reflect the Al Qaeda leadership’s own effort to assert more influence over the jihadist elements of the Syrian insurgency and not side with one faction or another.
The statement said Al Qaeda disapproved of the Islamic State of Iraq and the Levant and had “ordered it to stop” acting in Al Qaeda’s name.
According to a translation of the statement quoted by the Associated Press, Al Qaeda condemned the rebel infighting in Syria. “We distance ourselves from the sedition taking place among the mujahedeen factions and of the forbidden bloodshed by any faction,” the statement was quoted as saying.
Angered by what they called the arrogant behavior of fighters loyal to the Islamic State of Iraq and the Levant and the organization’s tendency to commandeer resources, other Syrian groups began to violently clash with it, starting in late 2013.
Many of the clashes were deadly and most were confined to the northern and eastern parts of Syria, where the rebellion against Assad is most pronounced.
Although the Islamic State of Iraq and the Levant shares the common insurgent goal of deposing Assad and his followers, it wants to replace the government with a strict Islamic state.
In early January, another Al Qaeda-linked group in Syria, the Nusra Front, proposed a cease-fire in the rebel infighting and the establishment of a special Islamic court to resolve any disputes, but that solution apparently never advanced.
Monday’s announcement also appeared to be a move by Al Qaeda leader Ayman al-Zawahri to reassert the terror group’s control of the jihad movement across the Middle East amid a rapid increase in extremist groups over the past three years.
Abu Bakr al-Baghdadi, the head of Al Qaeda’s branch in Iraq, formed the Islamic State last spring despite direct orders by Zawahri not to do so. Zawahri named the Nusra Front as Al Qaeda’s branch in Syria.
Now, the break will probably 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 Zawahri’s influence will be whether his decision leads fighters to quit the Islamic State.
Washington has viewed the increasing influence of Islamic extremism in Syria’s rebel movement with unease. Yesterday, State Department spokesman Jen Psaki noted that both the Islamic State and the Nusra Front are considered terrorist organizations.
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 Syria on Monday, the government extended its intense aerial campaign against rebel-held areas of the northern city of Aleppo, conducting a series of airstrikes that killed at least 18 people, including five children, the Associated Press reported, quoting activists.
Assad’s air force has pounded opposition areas of the divided city since mid-December, reducing apartment blocks to rubble and overwhelming already strapped hospitals and medical clinics with the wounded.
On Sunday, government aircraft also targeted areas of east Aleppo under rebel control, killing nearly 40 people.
Monday’s air raids hit the districts of Hanano, Qadi Askar, and Mouwasalat, the Britain-based Syrian Observatory for Human Rights said. The group, which monitors the conflict through a network of activists, said helicopters dropped crude bombs — barrels packed with explosives, fuel, and scraps of metal — on the neighborhoods, causing immense damage.
The Syrian government has not relented in its bombardment of Aleppo since launching what appeared to be a concerted aerial campaign there late last year.
Over a two-week stretch in December alone, activists say airstrikes killed more than 500 people, the Associated Press reported.
Syria’s opposition has pointed to the air raids as evidence that Assad has little interest in peace efforts, despite sending a delegation to Switzerland last week for UN-sponsored negotiations aimed at ending the war.
Last week’s face-to-face talks took between the Assad’s government and an opposition coalition group ended in acrimony, although Lakhdar Brahimi, the special UN envoy for Syria, said further talks could take place later this month.
In what appeared to be a concession by Brahimi to the Syrian government aimed at ensuring its participation in another round of talks, the United Nations announced Monday that Brahimi’s deputy, Nasser al-Kidwa, was resigning, effective this week.
Syrian officials had objected to Kidwa, a former foreign minister of the Palestinian Authority, which is negotiating with Israel over a future Palestinian state.