BEIRUT - The shadowy leader of one of Syria's most powerful rebel groups pleaded with his comrades to stop the spread of rebel infighting in opposition-held territories, warning it threatened to upend gains made against Syrian government forces.
The rare recording by Abu Mohammed al-Golani, the head of the extremist Nusra Front, underscored the seriousness of the clashes between a chaotic mix of Syrian rebel brigades against fighters of the al-Qaida linked Islamic State in Iraq and the Levant.
"The foreigners and supporters will pay the price for losing this great jihadi fighting field," said al-Golani in the recording uploaded to a militant website, referring to foreign and local rebels. "The (Assad) regime will revive itself after it was close to disappearing. The West and the Shiites will find a place to enter into this battle," he said.
The infighting began Friday, after residents reported that the extremist fighters tortured and killed a popular doctor in the northern city of Aleppo.
It spread from the northern province of Aleppo to nearby Idlib, then to the eastern province of Raqqa, a stronghold for the Islamic State in Iraq, in what was the most serious rebel infighting since the uprising against President Bashar Assad began in March 2011.
The clashes against radical extremists add another layer of complexity to the Syrian conflict, less than three weeks ahead of a planned international peace conference to try to resolve the civil war.
The Nusra Front and its rival al-Qaida linked group, also known as ISIL, are ideologically similar: both are extreme Islamic groups, loyal to al-Qaida. But the Nusra Front is dominated by Syrian fighters, and sees its first priority as overthrowing Assad. ISIL sees itself as trying to build Islamic rule.
Since March, it has muscled into areas once controlled by other rebels.
Tensions simmered against the extremist group for months, for detaining foreign reporters, Syrian activists, rival rebel fighters and others critical of their rule. They have also detained citizens perceived to have disobeyed their extreme rules.
Those grievances were heightened because the Islamic State in Iraq and the Levant leadership is mostly foreign, stirring more resentment.
"The mistaken policies that ISIL practiced had a big role to play in igniting this conflict," said al-Golani. He said they were trying to form a council to halt the fighting.
The fighting has added extra danger for dozens of Syrians and foreigners believed detained by Islamic State in Iraq and the Levant fighters.
On Tuesday, Syrian activists said four colleagues who were detained by the extremist group in the northern city of Aleppo were killed.
They said the men were killed during fighting Monday around an eye hospital that was an ISIL stronghold in Aleppo.
Three worked for an opposition outlet called "Shada al-Hurriya" and were seized in December, said the Syrian Journalists Association and an activist, Abu Saleh al-Halaby. The fourth slain colleague was the media man for the Nusra Front, they said.
Rami Abdurrahman of the Britain-based Syrian Observatory for Human Rights also reported that five people were killed, but couldn't confirm their identities. The Observatory and other activist groups rely on a network of people in Syria.
Adding to those concerns, the Observatory said that three Syrians captured months ago by the extremist group were found dead in the eastern Syrian town of Kafar Zeita after a clash between their fighters and other rebels. Other Syrians who escaped the extremist group's detention in the northern province of Idlib said their captors decapitated two other detainees.
On Tuesday, the most serious fighting was in Aleppo and in the extremist's group chief stronghold of Raqqa.
The fighting adds another hardship to an already-suffering population.
The Syrian Observatory and another group, the Aleppo Media Center said government aircraft strike killed at least 10 people, including children in the northern town of Bzaa. Another strike in the Haydariyeh quarter of Aleppo killed at least six civilians. They said the strikes occurred Monday.
The infighting also added more uncertainty to the so-called Geneva peace conference, which is to open Jan. 22 in Switzerland to try resolve the Syrian conflict.
But that likelihood appeared distant.
Meanwhile in Damascus, the Syrian information minister said citizens would urge Assad to seek re-election next July, and that he would win the vote. Syria's war began as an uprising three years ago against Assad's rule.
Minister Omran al-Zoubi said the president's decision to reclaim the nation's highest office, would however, for Assad to decide.
Zoubi's Tuesday comments at a Damascus press conference are the latest in a series of hints by Syrian officials that Assad may seek re-election.
Also Tuesday, the United Nations pleaded with international donors to "prevent a lost generation of Syrian children."
In a statement, a series of U.N. agencies and aid groups pleaded with donors for $1 billion to fund programs to "lift Syrian children out of misery, isolation and trauma."
Aid groups estimate that least half of Syria's millions of displaced are children. Tens of thousands of Syrian children have been forced to leave school to find menial jobs, as their families fall into poverty.
Other families have married off young girls, finding no other way to support them.
The U.N. also said Tuesday that it had stopped updating the death toll from Syria's civil war, confirming it could no longer verify the sources of information that led to its last count of at least 100,000 in late July.
Rupert Colville, a spokesman for the U.N. Office of the High Commissioner for Human Rights, blamed the failure to provide new figures on the organization's own lack of access on the ground in Syria and its inability to verify claims made by other organizations.
Colville said the U.N. could not endorse anyone else's count, including the widely quoted figures from the Observatory, whose latest tally is more than 130,000 killed in violence in Syria since March 2011.
With reporting by Albert Aji in Damascus and Zeina Karam in Beirut