A new report by Human Rights Watch (HRW), “You Can Still See Their Blood,” documents “serious abuses committed” by Syrian insurgents during an offensive that began in Latakia on Aug. 4.

Latakia is a coastal stronghold for the Assad family. But the rebels did not target only regime assets in the offensive, dubbed the “Operation to Liberate the Coast.” They also unleashed sectarian-motivated violence in more than 10 Alawite villages.

HRW “has collected the names of 190 civilians who were killed by opposition forces in their offensive on the villages, including 57 women and at least 18 children and 14 elderly men.”

Of the 190 civilians, at least 67 were summarily executed or “unlawfully killed” by the rebels. “There is no evidence that they could have posed, or could have been perceived to pose, any threat to the fighters,” HRW writes.

Al Qaeda’s two affiliates in Syria, along with allied extremist groups, led the offensive in the Latakia countryside and were principally responsible for the slayings. Free Syrian Army fighters also took part in the operations, but HRW found that their precise role in the attacks on civilians is not clear.

Twenty or more groups participated in the rebel operations. However, HRW lists five groups as “among the principle planners, fundraisers, and executors of the offensive” in Latakia.

The list includes both of al Qaeda’s affiliates in the country, the Al Nusrah Front and the Islamic State of Iraq and the Sham (ISIS). Two other groups that are known to be closely linked to al Qaeda’s affiliates, Ahrar al Sham and Jaish al Muhajireen wal Ansar (or “Army of Emigrants”), helped lead the fight. And the fifth group is Suquor al Izz, which is openly jihadist.

According to HRW, the evidence shows that “members of all five of these groups” are directly linked “to specific incidents that amount to war crimes.”

Weeks after Syrian forces pushed back the rebel offensive, the ISIS and Jaish al Muhajireen wal Ansar have continued to hold hostages from the villages. To this day, “over 200 civilians, the vast majority of whom are women and children” are being held by these two groups, which “led the opposition offensive.”

According to “an opposition military leader from Latakia” interviewed by HRW, Jaish al Muhajireen wal Ansar transferred “control over the hostage file” for negotiations to Ahrar al Sham sometime in late September.

Other rebel groups took part in offensive

HRW lists the other rebel groups that took part in the fighting, but emphasizes that their role in the abuses is unknown.

Fighters under the command of Salim Idriss, who heads the Free Syrian Army, joined the rebel offensive. But one source told HRW that they did not show up until after Aug. 4, when the atrocities are thought to have been committed, and their overall role in the fighting was “limited.” Still, Idriss was eager to highlight the FSA’s role, releasing a video on Aug. 11 that was “apparently filmed” in the Latakia countryside.

Among the other rebel groups that fought in Latakia is Sham al Islam, which is led by a former Guantanamo Bay detainee known as Ibrahim Bin Shakaran.

A leaked threat assessment authored by Joint Task Force Guantanamo (JTF-GTMO) identified Bin Shakaran as a “high-ranking member” of the theological commission of the Moroccan Islamic Combatant Group, an al Qaeda-affiliated terrorist organization. The Defense Department has said that Bin Shakaran became a recruiter for al Qaeda in Iraq after his transfer from Guantanamo to his native Morocco in 2004. Another ex-Guantanamo detainee, known as Abu Hamza al Maghrebi, was killed while fighting for Sham al Islam.

Foreign fighters, funding, and other support

The HRW report warns that Turkey continues to serve as a gateway for foreign fighters entering Syria. During the operation in Latakia, “Abu Suhaib, the Libyan local leader of Jaish al Muhajireen wal Ansar, and his men … reportedly received medical treatment in Turkey,” the report reads.

HRW “identified several individuals, principally from Gulf countries” who financed the rebels’ operations. The financiers include Kuwaiti sheikhs and other foreign actors. According to HRW, there “is no evidence that the fundraisers and financiers knew at the time that they gave their support about the abuses that would or were taking place in Latakia countryside.”

Al Qaeda’s affiliates still cooperating in Syria

Although a leadership dispute between the Al Nusrah Front and the ISIS erupted in April, the two al Qaeda affiliates continue to cooperate throughout Syria. In addition to the offensive in Latakia, the groups collude against their common Kurdish enemies in Hasaka and Raqqah provinces. They have also reportedly fought alongside one another against Assad’s forces in Aleppo, and cooperated in Deir Izzor.

Beyond their cooperation with one another, the Latakia offensive shows that al Qaeda’s affiliates and their extremist allies often lead other brigades into battle as well.

Thomas Joscelyn is a Senior Fellow at the Foundation for Defense of Democracies and the Senior Editor for FDD's Long War Journal.

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