BEIRUT — Syrian rebels battled al-Qaeda-affiliated fighters across northern Syria on Saturday in an attempt to stem the sudden rise in influence of the extremists who have been staging attacks and conquering territory from Baghdad to Beirut.
At the same time, Iraqi government forces fought to contain an expanding revolt in the western province of Anbar by Sunni tribes, some of which have linked up with al-Qaeda militants to score significant gains in recent days.
The battles on both sides of the border signaled a defining moment for the increasingly entwined conflicts in Iraq and Syria, which have enabled the al-Qaeda-linked Islamic State of Iraq and Syria (ISIS) to emerge as one of the region’s most powerful players.
On Saturday, Iraqi government troops fired shells into the city of Fallujah, which was overrun by al-Qaeda fighters this past week. At least seven civilians were killed, according to residents, but the government made no apparent headway against the insurgents, who are fighting with tribesmen in a broad revolt against the Shiite-dominated government of Prime Minister Nouri al-Maliki.
In Washington, the State Department noted that some tribal leaders have turned against the al-Qaeda fighters, including in the provincial capital of Ramadi, where tribes have allied with police and succeeded in ejecting militants from parts of the city they had seized.
From Israel, Secretary of State John Kerry said the United States is ready to provide help in every way it can short of a return of U.S. forces to Iraq. He would not provide specifics, but a possible form of quick U.S. help would be additional weaponry for the Iraqi security forces.
The al-Qaeda affiliates trying to assert control in Iraq and Syria are “the most dangerous players in this region. Their barbarism against the civilians of Ramadi and Fallujah and against Iraqi security forces is on display for everybody in the world to see,” Kerry said during a press conference Sunday.
Kerry said that the fight “belongs to the Iraqis.”
“We will stand with the government of Iraq and with others who will push back against their efforts,” Kerry continued. “We are going to do everything that is possible to help them.”
More than 1,300 American servicemen died defending the province of Anbar from attacks by al-Qaeda-linked militants during the Iraq war from 2003 to 2011, but American influence in Iraq has waned dramatically since the troops withdrew. The war next door in Syria has further facilitated the resurgence of the Islamic State of Iraq, as it was known when U.S. troops were present, by giving it space to organize and rearm.
“This is a fight that is bigger than just Iraq,” Kerry said. “The rise of these terrorists in the region, and particularly in Syria, and through the fighting in Syria, is part of what is unleashing this instability in the rest of the region. That’s why everybody has a stake.”
In the first indication that ISIS may be reaching into Lebanon as well, the group said it had carried out a suicide bombing Thursday in the Hezbollah-controlled southern suburbs of Beirut. The claim could not be verified, but ISIS warned that more such attacks would follow against the Shiite Lebanese movement, which has dispatched fighters to defend Syrian President Bashar al-Assad against the rebels.
But the uprising against ISIS in parts of rebel-held Syria offered the first sign of a reversal to months of steady advances by the extremists, who rely heavily on foreign volunteers from across the Muslim world. Since the group announced its expansion from Iraq into Syria last April, it has rapidly extended its control over large swaths of northern Syria, eclipsing the more moderate rebels who spearheaded the original revolt against Assad.
Activists hailed the revolt by the rebels as a “second revolution,” one they hope will shift the momentum on the battlefield in favor of moderates.
“This is more important than fighting the regime,” said Mohammed Azzouz, an anti-government activist from the eastern city of Raqqah who was forced into exile in Turkey by the extremists late last year.
The fighting began Friday and spread Saturday after ISIS released the body, bearing marks of torture, of a popular commander from the Ahrar al-Sham brigade, an Islamist group that is not allied with al-Qaeda. But opposition has been growing more broadly to the brutal tactics and authoritarian behavior of the extremists, who have alienated citizens with their harsh interpretation of Islamic justice, including beheadings, lashings and bans on smoking and music.
A wide range of rebel units participated in the fighting across the provinces of Idlib and Aleppo, which were the first to eject government forces after Syrians rose up against the Assad regime in 2011. Units of the newly formed Islamic Front as well as more moderate brigades loosely affiliated with the umbrella Free Syrian Army have joined the fighting.
The Turkish government closed key crossings into Syria as fighting spread Saturday, with rebels claiming they had ejected ISIS fighters from the Idlib province towns of Saraqeb, Maarat al-Numan and the border town of Bab al-Hawa, and the Aleppo provincial towns of Marae and Tal Rifaat.
The rebels killed three top ISIS commanders, from Chechnya, Tunisia and Saudi Arabia, and detained more than 170 fighters, according to Abdulrahman al- Jalloud, an activist in Bab al- Hawa. The rebels also freed scores of Syrians who had been detained by ISIS, he added.
Much of the fighting against ISIS was carried out by the Syrian Revolutionary Front, another newly formed alliance that includes secular brigades seeking to present themselves as a bulwark against al-Qaeda.
The ISIS extremists “have lost the support of the people because they treated them badly. They were cutting off people’s heads all of the time to scare them in the name of religion,” said Col. Qassim Saadeddine, a spokesman for the Revolutionary Front.
The battles could become a major turning point if more rebel units join from other areas, said Aymenn Jawad al-Tamimi, a fellow at the Philadelphia-based Middle East Forum who monitors jihadist activity.
“ISIS are clearly on the defensive and taking precautionary measures while being driven out of a number of areas,” he said.
In a statement, ISIS indicated that it is feeling pressure. The group threatened to withdraw its fighters from rebel-held areas of Aleppo within 24 hours if the challenge persists, potentially leaving residents there vulnerable to regime forces.
“We call upon the people of Aleppo to take the matter seriously, for the withdrawal of the Islamic State from any of those points will mean the invasion of liberated Aleppo by the criminal regime,” ISIS warned in a statement posted to its Twitter account.
It called the fighting “an evil plan” to eliminate al-Qaeda ahead of peace negotiations planned in Geneva this month, at which world powers are hoping the government and the opposition will hold face-to-face talks for the first time.
Suzan Haidamous and Anne Gearan contributed to this report.