Who's fighting whom in Syria?

A quarter-million lives lost, millions forced from their homes, and still the suffering continues. On Friday, the United Nations Security Council voted unanimously on Friday to back a plan put forward to end the war in Syria, despite its soft demands towards the regime.  Yet how to untangle the nearly 5-year-old Syrian conflicty is a puzzle.

Here is a rundown of who's fighting whom, and why, in Syria:

Two Wars

There are two wars going on in Syria.  First came the rebellion against Syrian President Bashar Assad.  Assad succeeded his father as authoritarian leader of Syria in 2000. He responded to peaceful Arab Spring protesters in 2011 with a crackdown so brutal that it sparked an armed revolt that still rages.

Then came an invasion by the Islamic State, which Assad considers one of many "terrorists" arrayed against him.

Formerly known as al-Qaeda in Iraq, the Islamic State is infamous for videotaped beheadings, mass murder and systematic rape of captive women. Syria's chaotic war opened the way for the Islamic State to expand across the border in 2013. IS has seized about a third of Syria, and has placed its capital in the northern Syrian city of Raqqa.

A US led coalition is fighting the Islamic State from the air, while the CIA is secretly arming and assisting rebels fighting Assad.

Who's who in Syria's war? 

With Assad: 

—The Syrian army and pro-government militias.

— Russia. Longtime allies of Assad, the Russians set up a base in Syria this fall that launches airstrikes and added cruise missiles fired from the sea. Russia says its campaign is meant to weaken Islamic State and other fighters it considers "terrorists".  

—Iran. It bolstered Assad by sending weapons, military advisers, millions of dollars' worth of aid, and Revolutionary Guard troops, as well as rallying Shia fighters from

CIA has been running an operation providing weapons, money and training to Syrian rebels, including missiles to destroy Russian-made armoured vehicles.

Lebanon's Hizballah militia and elsewhere in the Middle East.

Against Assad:

—The Free Syrian Army. A loose coalition of dozens of moderate-leaning armed factions in Syria. They get backing from the West, including the US.

— Al-Qaeda and its allies. Al-Qaeda has severed ties with the Islamic State group. Its Syrian branch is the powerful Nusra Front, and allies in the fight against Assad include the ultraconservative Ahrar al-Sham and Islamic fighters from Russia's restive Chechnya region. Nusra is also fighting the Islamic State. 

—The United States. While pushing for Assad's removal, the US hasn't openly taken up arms against him, only the Islamic State. President Barack Obama threatened air strikes against Syria after hundreds of civilians were killed with sarin gas in 2013.   Syria, without acknowledging using nerve gas, agreed to relinquish its chemical weapons stockpile in an agreement with the US and other nations.

Covertly, the CIA has been running an operation providing weapons, money and training to thousands of Syrian rebels, including missiles to destroy Russian-made armoured vehicles. 

—Turkey. An early supporter of the rebels, especially Turkmen fighters, who are from a Syrian minority of Turkish descent and mostly live near the border with Turkey.

— Saudi Arabia and Gulf allies. They finance a number of anti Assad groups, including Sunni extremists, in hopes of toppling Assad. Some are also part of the US-led military coalition.

Who's who in the IS fight? 

The Islamic State Group 

— The CIA estimates that IS has 20,000 to 30,000 fighters spread between Syria and Iraq. Its skillful use of social media lures young recruits from around the world to the territory where the group says it's building its "caliphate," or state ruled by a supreme religious leader.   IS makes millions from selling oil, ransoming hostages and collecting taxes in the territory it controls. 

Against the Islamic State: 

— Kurds. The Kurds who live in northern Syria and bordering countries make up some of the fiercest opponents of IS. Their main forces are the People's Protection Units, known by the acronym YPG.

— Syrian Democratic Forces. A US backed alliance drawing from a mix of religious and ethnic groups, including many Kurds.

— United States and allies. An American-led coalition has launched thousands of airstrikes against IS targets, the vast majority conducted by the US military. Other coalition members who have taken part since the air campaign began in September 2014 are: Australia, Bahrain, Britain, Canada, France, Jordan, Saudi Arabia, Turkey and the United Arab Emirates.

After the Paris attacks, Germany joined in a noncombat support role.

The only US ground forces in Syria are a contingent of roughly 50 special operations troops who recently began working with local Syrian fighters trying to break the Islamic State's grip on Raqqa, its self-declared capital. A US project intended to train and equip moderate Syrian opposition forces was abandoned as ineffective.

— Saudi Arabia and allies. They've been carrying out air strikes against the Islamic State. This week Saudi Arabia announced the formation of a new 34-nation "Islamic military alliance" to fight IS and work together against terrorism. 

— Syria. Assad's government has done little to counter the rise of IS, instead focusing on its fight against rebel forces. Officially, Assad says all Syrians should join together to battle the Islamic State group as a common enemy.

Russia. Says it's targeting IS fighters, even though many of its attacks go elsewhere.

Assad's fate

Since the Syrian war began, President Barack Obama and his secretaries of state and defence have declared more than a dozen times that Assad must step down. But going into the latest Syria talks, Secretary of State John Kerry softened the position saying "the United States and its partners are not seeking so-called 'regime change.

The Russians have long stood up for Assad, a long-time ally who assures that Syria remains Russia's foothold in the Middle East. Russia has argued that Assad and his army are the only force positioned to defeat the Islamic State.  

But lately Russia has emphasised finding a "political solution" to the Syrian crisis, which might mean giving up on Assad, and says the decision should be the Syrian people's to make.
 
Turkey v Russia 

The tension between Turkey and Russia goes deeper than being on opposite sides of the Assad question. 

Turkey wants to protect the Turkmen population battling Assad. Russian warplanes have targeted those Turkmen fighters.   Turkey shot down a Russian warplane recently, saying the jet was flying in Turkish airspace, which has ratcheted up tensions between the two nations. 

Turkey and the Kurds 

Turkey publicly opposes the Islamic State but Turkey's role in the anti-Islamic State campaign is muted by its own war with some of the fiercest fighters in the battle against IS: the Kurds. Turkey has been battling Kurdish rebels known as the PKK and their struggle for autonomy for decades.