Syrian Civil War Explained

As the Syrian conflict enters its seventh year, more than 465,000 Syrians have been killed in the fighting, more than a million injured and over 12 million Syrians - half the country's prewar population - have been displaced from their homes.

In 2011, what became known as the Arab Springrevolts toppled Tunisian President Zine El Abidine Ben Ali and Egyptian President Hosni Mubarak

That March, peaceful protests erupted in Syria as well, after 15 boys were detained and tortured for having written graffiti in support of the Arab Spring. One of the boys, 13-year-old Hamza al-Khateeb, was killed after having been brutally tortured.

The Syrian government, led by President Bashar al-Assad, responded to the protests by killing hundreds of demonstrators and imprisoning many more. In July 2011, defectors from the military announced the formation of the Free Syrian Army, a rebel group aiming to overthrow the government, and Syria began to slide into civil war.

Several Arab states, along with Turkey, have provided weapons and materiel to rebel groups in Syria. The governments of majority-Shia Iran and Iraq support Assad, as does Lebanon-based Hezbollah, while Sunni-majority states including Turkey, Qatar, Saudi Arabia and others staunchly support the rebels.

Rebel groups

Since the Free Syrian Army formed in 2011, many new rebel groups have joined the fighting in Syria, including ISIL, Jabhat Fateh al-Sham, Iran-backed Hezbollah, and the Syrian Democratic Forces (SDF) dominated by the Kurdish People's Protection Units (YPG).

What caused the uprising?

Initially, lack of freedoms and economic woes fuelled resentment of the Syrian government, and public anger was inflamed by the harsh crackdown on protesters. Successful uprisings in Tunisia and Egypt energised and gave hope to Syrian pro-democracy activists. Many Islamist movements were also strongly opposed to the Assads' rule.

In 1982, Bashar's father, Hafez al-Assad, ordered a military crackdown on the Muslim Brotherhood in Hama, which killed between 10,000-40,000 people and flattened much of the city.

Although the initial protests in 2011 were mostly non-sectarian, armed conflict led to the emergence of starker sectarian divisions. Minority religious groups tend to support the Assad government, while the overwhelming majority of opposition fighters are Sunni Muslims.

Most Syrians are Sunni Muslims, but Syria's security establishment has long been dominated by members of the Alawite sect, of which Assad is a member.

The sectarian split is reflected among regional actors' stances as well.

Even global warming has been claimed to have played a role in sparking the 2011 uprising. A severe drought plagued Syria from 2007-10, spurring as many as 1.5 million people to migrate from the countryside into cities, which exacerbated poverty and social unrest.