The flames of Syria's mounting violence and civil strife are being fanned by a sinister new player: al-Qaeda.
After a pair of suicide car bombings that killed 28 people at state security facilities in Aleppo, the leader of al-Qaeda, Ayman al-Zawahiri, publically threw his terrorist organization's weight behind the Syrian opposition.
The ability of the fugitive al-Qaeda leader to directly influence or organize the spiralling violence across Syria may be limited. But the Aleppo bombings, like those in Damascus in late December and early January, bore the hallmarks of operations carried out in Iraq by the al-Qaeda-linked faction there.
U.S. officials told American reporters on the weekend they "would not be surprised" if it was al-Qaeda that carried out Friday's bombings as well as the earlier attacks in Damascus.
The message from Mr. al-Zawahiri, calling on Muslim fighters from Iraq, Jordan, Lebanon and Turkey to go to Syria and join a war of jihad against Bashar al-Assad's "pernicious, cancerous regime," was the last thing the Syrian opposition wanted to hear.
"Al-Qaeda has no sympathizers among the protesters," said Ammar Abdulhamid, a Syrian activist and fellow at the Foundation for Defense of Democracies in Washington.
"The protesters' goal remains the establishment of a democratic civil state," he said, and "they all understand that al-Qaeda involvement would ultimately undermine this goal."
The disparate opposition groups fighting to oust the powerful al-Assad forces have struggled to gain international support for their cause, in part by framing it as the aspiration of all Syrians regardless of their sectarian or religious bent. They worry that al-Qaeda could undermine that goal as well, although some experts say their worry is misplaced.
"It may be the last thing they want to hear, but it's not likely to make any practical difference," said Barry Rubin, author of The Truth About Syria, referring to the call to arms from Mr. al-Zawahiri.
"Those who have come out against Assad will stick to the side they've chosen, and they'll just try to ignore al-Qaeda's presence," he added.
It could prove difficult to ignore.
Indeed, Iraqi officials told reporters on the weekend that for the past four months, there has been a stream of Iraqi fighters and weapons flowing into Syria from Iraq to support the anti-Assad movement.
The fighters and weapons "are being smuggled from Mosul through the Rabia crossing to Syria, as members of the same families live on both sides of the border," said Iraqi Deputy Interior Minister Adnan al-Assadi.
"We have known about the jihadists' role for months," said Alastair Crooke, the Beirut-based director of Conflicts Forum. "People have just chosen to turn a blind eye to it."
Mr. Crooke, a former analyst in Central Asia with British MI6, said that "almost since the outset, Syrians who fought with Zarqawi in Iraq, have been involved" in the campaign to oust President al-Assad, referring to the late Abu Musab al-Zarqawi, leader of al-Qaeda of Iraq until his killing in 2006.
There are those fighters who returned to Syria, Mr. Crooke said, as well as an influx of jihadists from other countries. "These people," including al-Qaeda, he said, "are much more anti-Shia than pro-democracy. After Syria, they want to take the fight to Iraq and on to Iran."
That, Mr. Crooke said, is what Iraqi Prime Minister Nouri al-Maliki was referring to last year when he warned that the ousting of Bashar al-Assad could lead to a regional sectarian conflict, pitting Sunni against Shiite.
Syrian President al-Assad has been insisting for some time that the opposition he faces includes what he calls "foreigners," among them al-Qaeda and other armed jihadist elements. The main coalitions of Syrian opposition groups, though, say they are fighting for democratic change in their country and an end to the long-ruling Assad dictatorship. They want no part of al-Qaeda.
"Al-Qaeda and the Assads are two faces of the same coin of sectarian hatred," said Mr. Abdulhamid, the Syrian activist. "Both seek to stoke fires that we want to extinguish."
The al-Qaeda message was followed Sunday by the declaration of jihad by Jordan's increasingly powerful Muslim Brotherhood. The group called it "an Islamic duty" to support Syria's rebel army.
The surge in jihadist language came as the Arab League met in Cairo to decide its next move, a week after its peace plan calling for Mr. al-Assad to hand over powers to his vice-president was vetoed in the United Nations Security Council by Russia and China.
The League voted to ask the Security Council to dispatch a joint UN-Arab League monitoring group to Syria to report on the situation inside the country. Syria quickly dismissed the notion as an unacceptable intervention.
In his eight-minute video-taped statement, entitled "Onwards, Lions of Syria," Mr. al-Zawahiri urged Syrians to oppose help from the Arab League and "its corrupt agent governments."
"There is no treatment for [the Assad regime]other than removal" he said. "Don't depend on the West and Turkey, which had deals, mutual understanding and sharing with this regime for decades and only began to abandon it after they saw it faltering."
"Instead," he added, "depend on Allah alone and then on your sacrifices, resistance, and steadfastness."
Born in Egypt, Mr. al-Zawahiri, who trained as a physician, took over al-Qaeda after Osama bin Laden was killed last May by a U.S. special forces raid on his hideout in Pakistan.
In July, he urged Syrian protesters to direct their movement also against Washington and Israel, denouncing the United States as insincere in showing solidarity with them.