Is This the Most Disgusting Atrocity Filmed in the Syrian Civil War? Even by the standards of Syria's ever-worsening stream of atrocity and massacre videos, the latest footage from the country cannot fail to shock for its sheer savagery. The video, posted on May 12 but filmed on March 26 near the Syrian town of Qusayr, on the border with Lebanon, opens by calmly filming a rebel commander cutting open the chest of what we assume is a deceased pro-Bashar al-Assad fighter, removing his heart and liver with surgical precision and sang-froid. The cameraman jokes with the commander, telling him, "God Bless you Abu Sakkar, it looks like you are drawing a love heart [on his chest]!" The commander, the man called Abu Sakkar, then picks up the bloody liver and heart and speaks directly into the camera, delivering a chilling threat: I swear to God, you soldiers of Bashar, you dogs, we will eat from your hearts and livers! O heroes of Bab Amr, you slaughter the Alawites and take out their hearts to eat them! As men in the background shout Allahu Akbar! (God is Great!), Abu Sakkar ends the video by putting the dead man's heart in his mouth and ripping off a chunk of the bleeding organ. Mutilation and cannibalism, punctured by deeply sectarian language, point to the horrifying sectarian violence that is starting to engulf parts of Syria. Journalists contacted by Human Rights Watch -- as well as the commander's own brother, in a meeting with Time magazine journalists -- have confirmed that the man in the video is indeed Abu Sakkar, a well-known rebel commander. Journalists who have met him report that he was one of the founders of the Farouk brigade, one of Syria's largest and most storied mainstream rebel militias, founded in the city of Homs in 2011. Abu Sakkar and his fellow fighters hail from the Baba Amr district of Homs, which came under one of the most brutal and intensive sieges mounted by the Syrian army during the two-year-long conflict. During the siege, which lasted from February to May of 2012, forces loyal to Assad pounded the district into rubble and decimated the ranks of local rebel fighters, as well as the civilian population trapped in the fighting. Journalists who met Abu Sakkar have described his militancy and fondness for guns. Last October, Abu Sakkar broke off from the mainstream Farouk brigade, and formed his own, more militant "independent" Omar al-Farouk brigade. Since then, he has placed himself at the forefront of an increasingly sectarian battle for control of the town of Qusayr, subjected to a massive Syrian government offensive reportedly backed by Hezbollah. The battle of Qusayr, strategically located near the Lebanese border and in a particularly diverse region of the country, is drawing Syria and the region into an even more dangerously sectarian direction. Controlling Qusayr is of crucial importance to both the armed opposition and to Assad's government. For the rebels, Qusayr is an important transit point for weapons and fighters headed toward Damascus. For Assad's government, the disruption of this weapons pipeline -- and the encirclement of the rebel forces besieging Damascus -- is currently one of its most important military objectives. A government victory in Qusayr may give Assad's forces an edge, strengthening its safe corridor to the coast and to the Alawite heartland that forms the core of its support base. The battle for Qusayr has also drawn in Hezbollah fighters from neighboring Lebanon, some of whom have been killed in fighting around the town and in Shiite villages in the area. Their role was acknowledged in a recent speech by Hezbollah's leader, Hassan Nasrallah, and is highlighted by the increasingly common "martyr" funerals for Hezbollah fighters killed in Syria. Sunni Salafi preachers in Lebanon have responded by calling on their followers to go fight in Qusayr to help their "Sunni brothers." The conflict's increasingly sectarian dynamic has not been limited to the province of Homs. On May 2, rebels in southern Damascus offered their own response to Nasrallah's speech: They dug up the grave of one of the most revered Shiite figures, a companion of the Prophet Mohammed and early follower of his cousin and son-in-law, Imam Ali, known as Hujr ibn Adi. Those who claimed to have carried out the desecration said they did it in the name of Islam and that they wanted to stop Shiites from worshiping Adi's bones, a practice considered heterodox among hardline Sunnis. On the same day as the desecration of the tomb, terrible images of dead and burned bodies, including those of children, emerged from the towns of Bayda and Baniyas in the coastal Alawite hinterland. There, local Sunni residents have accused pro-government fighters of carrying out retributive killings and executions in areas that supported the opposition. Abu Sakkar, the commander who apparently mutilated the dead soldier, has been an active participant in the sectarian violence and its regional spillover. In retaliation for the entry of Hezbollah fighters into the battle of Qusayr, he led the shelling of Shiite villages in the Bekaa Valley of Lebanon. The shelling killed a 30-year-old man and a 13-year-old boy, and wounded three others. Abu Sakkar defended his actions to a journalist: Yesterday [April 14], Hezbollah bombarded Qusayr, Nahriyeh, Burhaniyeh, and Saqarji from its positions in Qasr and Hosh Sayid Ali. They bombed civilians and killed many women and children...If we have to, we will target civilians just like they do. Our civilians are not less valuable than theirs. Hezbollah is killing arbitrarily in Syria...Yesterday, we responded. We hit back at Hezbollah's positions. Abu Sakkar is just one man, and there are many other armed fighters in Syria who reject such sectarian actions and would be horrified by the mutilation and desecration of a corpse -- let alone an act of cannibalism. But he is a commander in a decisive battle in Syria -- hardly a marginal figure. Syria's sectarian turn presents a danger not just for Syria itself, but for the stability of the entire region, which has grown increasingly entangled in the Syrian morass. Lebanon has seen Shiite villages shelled from Syria, Hezbollah's involvement in Syria has caused some radical Sunni clerics in Lebanon to respond with their own call to jihad in Syria, and deadly violence sporadically breaks out between the pro-Assad Alawite neighbourhood of Jabal Mohsin and its hardline Sunni neighbors in the northern Lebanese city of Tripoli. In Iraq, tensions between the Shiite-controlled government of Prime Minister Nouri al-Maliki and the country's Sunni communities are at an all-time high after the April 23 crackdown on a Sunni protest camp in the northern city of Hawija that killed at least 40 civilians. The recent double car bombing in the Turkish border town of Reyhanli that killed at least 46 -- for which the Turkish government blamed pro-Assad militants -- has brought Turkey to the brink of conflict with Syria and provoked attacks by Turkish residents against Syrian refugees in the town. What can be done in the face of the Abu Sakkar's brutal savagery? Nothing can fully counter the ever-increasing vortex of killing and brutality as long as the conflict continues. But there are some steps that can and should be taken to push back against the growing tide of sectarian violence, and to make clear to people who are still listening that those responsible for such reprehensible acts will be held accountable. The U.N. Security Council granted the International Criminal Court (ICC) jurisdiction to investigate serious crimes in Libya following a crackdown on peaceful protesters. Yet due to opposition by some members of the Security Council -- including, most prominently, Russia and China -- the ICC has been unable to do the same in response to events in Syria, despite two years of conflict and atrocities. Action by the Security Council would send a powerful message to all sides of the Syrian conflict that abuses such as those committed by Abu Sakkar -- as well as those committed in even greater numbers by the Syrian government -- will ultimately be prosecuted as war crimes and crimes against humanity. The work of the ICC will be only one piece of the larger accountability effort needed in the wake of this conflict -- national trials, documentation, truth telling, reparations, and vetting will also be necessary -- but it is a crucial step, given the pervasive climate of impunity currently plaguing Syria. This gruesome video reinforces the need for the Syrian National Coalition and the Free Syrian Army to take all possible steps to prevent such abuses by anyone under their command and to hold those responsible for war crimes accountable -- as well as to urge all anti-Assad forces to do everything they can to keep weapons from reaching Abu Sakkar's brigade. Two years of brutal war -- in which more than 70,000 have died and an entire population has been brutalized by constant violence -- has left deep wounds. It has also created fissures that threaten to tear Syria apart in an even more violent round of sectarian, neighbor-to-neighbor killings. Abu Sakkar's words suggest that for him the enemy is no longer simply the other side's armed men in uniform: it is the Alawite and the Shiite communities. He will have counterparts in the pro-government Shabiha and the Syrian armed forces for whom the enemy are simply Sunnis. And as Iraq's civil war demonstrated, when communities rather than armies are seen as the enemy, the violence can be characterized by singular brutality and deadliness.