The men’s hands are tied tight behind their backs; they lie on concrete floor. The beating comes in sharp bursts as Syrian soldiers kick them in the stomach and batons crunch against heads. A soldier leans forward, amid jeers and laughter, and touches a flame to a prisoner’s head. He writhes and cries out, his hair ablaze. The scene was recorded on a video, one of many showing the brutality of Syria’s civil war, now approaching a third bloody year.

Another video earlier this year showed members of the rebel group Islamic State in Iraq and Syria (ISIS) executing three Syrian soldiers in the eastern city of Raqqa. The men were on their knees and blindfolded. A masked man walked casually behind them, hammering rounds into their heads before a cheering crowd.

All kinds of brutality and terror are gripping Syria.

The Syrian regime has fired long-range ballistic missiles into areas where it believes opposition fighters are holed up. Its attack helicopters and fighter jets have indiscriminately laid waste to neighbourhoods, terrorizing entire populations. Meanwhile in May, Shabiha — government-allied paramilitaries — stalked through the villages of Baniyas and Bayda, summarily executing 248 people; reports by watchdogs found that many of the dead had been knifed or bludgeoned to death. According to a July Human Rights Watch (HRW) report, tens of thousands of Syrians have disappeared into regime prisons where torture including “the use of electricity, burning with acid, sexual assault and humiliation, the pulling of fingernails and mock execution” is rife.

The opposition has become radicalized. ISIS takes swords and knives to throats, killing those who dare oppose it. The al-Qaida-linked Jabhat al-Nusra’s (JN) suicide bombings have killed scores of civilians. Sharia is being implemented in rebel-held territory: a recent video showed a man being flogged 40 times for selling alcohol. On August 4, fighters from a variety of opposition groups launched a large-scale offensive in Latakia province, overrunning army positions and entering ten Alawite villages, according to a HRW report titled “You Can Still See Their Blood”. In the ensuing slaughter, opposition fighters attempted to kill entire families, unarmed and often fleeing for their lives. All told, 190 people were killed — including 57 women and 18 children, many executed summarily. More than 200 were taken hostage.

Over 100,000 Syrians have been killed. More than two million have fled to neighbouring countries, with five million displaced internally, according to UN estimates. Responsibility for Syria’s civil war lies initially with President Bashar al-Assad and his clique: their murderous assault on protesters left little choice but recourse to armed struggle. However, responsibility extends much further: aside from the US and its European partners, Saudi Arabia, Qatar, Russia, Iran, Turkey are all actors in the Syrian tragedy. As US Secretary of State John Kerry seeks to assemble these countries at Geneva 2, he needs urgently to curb US allies — in particular, Turkey, Qatar and Saudi Arabia — if the meeting is to yield any concrete results.

Cutting military and financial support to all armed factions, whether regime forces and allies, or opposition factions, could help drive down the Syrian death toll, and cool the contagious effect of the war on the region, notably in Iraq. Only then could real discussions of a negotiated settlement begin.

Russia and Iran need to stop providing the Syrian regime with military support (Scud missiles, thermobaric “vacuum” bombs or spare parts for T-72 tank and helicopters). Iran must withdraw its Revolutionary Guard Forces from Syria and pressure its Lebanese ally Hezbollah to do the same with its own fighters. Qatar and Saudi Arabia must stop financing large shipments of weapons (bought from Libyan arms bazaars and shipped off to insurgents in Syria, according to reports, with a first stop in Qatar before being channeled on via Turkey). Turkey must reestablish firm control over its southern border, and stop turning a blind eye to the weapons and fighters flowing into the rebel-occupied north of Syria. For southern Turkey has become a key transit point for foreign radicals heading into Syria, and the Turkish government has at best turned a blind eye to the 10,000 foreign extremists fighting the Assad regime inside Syria.

Turkey may now be recalibrating its Syria policy: signs of this are its seizure of around 1,000 rockets in Adana (presumably en route to Syria) and recent arrests of a number of al-Qaida operatives. Turkey has always claimed its Syria policy was based on a peaceful footing, while supporting what it calls “the Syrian people’s legitimate demands”. Yet, its intelligence services’ seeming use of Turkmen agents in northern Syria, coordinating arms movements to militants, contradicts such claims.

The international dimensions of the conflict have wildly escalated the insurgency: around 5,000 Syrians had been killed by November 2011, when international focus shifted sharply to Syria following the fall of Muammar Kaddafi in Libya. Iran and Saudi are waging proxy wars both for regional hegemony and ownership of Islam, fueling the sectarian nature of the war. Qatar, a tiny hydrocarbon island with big ambitions, is seeking influence wherever it can: in the Syrian context, through the Muslim Brotherhood and its allied militia. Money from private backers in the Arabian Gulf — some reported to be government figures — has led to a profusion of militia and at the same time accelerated fractures within the opposition, as they compete for resources.

For Russia, Assad is still its core Middle East ally, with a significant naval base ensuring Russia’s presence in the Mediterranean. Despite the recent diplomatic opening, it would be hard for Moscow to allow Assad to be forced from power. (Analysts note that Russia remains bitter after what it sees as its betrayal in Libya, where NATO far overstepped its mandate to protect civilians under United Nations Security Council Resolution 1973, instead acting to effect regime change.)

For Iran, Syria is a key conduit in its “axis of resistance” permitting the movement of arms to its Lebanese Shia proxy Hezbollah, which could open up a front against Israel. Britain and France (who together carved up the Levant following the Ottoman collapse) want to see the fall of a non-compliant regime, seeking influence in what they recognise as the close of the post-colonial era. Since the intervention in Libya, both countries have been accused of neocolonialism. France has historical ties with Syria, which was a French protectorate until independence at the end of the Second World War (reports indicate that French Special Forces have been moving military resources into Syria, in cooperation with Saudi Arabia and other Gulf states). The US is balancing the demands of its regional allies against President Barak Obama’s desire not to get embroiled in another Middle East war which would have little strategic value, mindful of the costly interventions in Afghanistan and Iraq.

With the different international agendas and complexities, if Geneva 2 does indeed take place, can a diplomatic solution rescue Syria from nearly three years of bloodshed?