More than Nine Years of Conflict in Syria

Syria's war since 2011 has involved a host of regional and international players, created millions of refugees and displaced, and left more than 380,000 people dead.

Here is a summary of the main events in the nine-year conflict:

- Revolt to repression -

In March 2011, protests break out to demand political change after four decades of repressive rule by the Assad dynasty.

President Bashar al-Assad's regime cracks down on demonstrations but rallies continue.

In July, an army colonel who has defected from the military sets up the Turkey-based opposition Free Syrian Army (FSA).

An armed rebellion erupts with support from Western and Arab countries. The rebels seize key territory, including large swathes of the third city Homs and a chunk of Aleppo, the second city.

- Air strikes -

In 2012, regime forces step up their crackdown, carrying out bloody operations, notably in the central city of Hama, a bastion of opposition to the Assad regime.

FSA fighters in July launch a battle for Damascus. The government retains control of the capital, but rebels seize parts of the suburbs.

From 2013, regime helicopters and planes unleash air strikes, some of them using barrel bombs, on rebel zones, according to the Syrian Observatory for Human Rights.

- Hezbollah, Iran -

The Iran-backed Lebanese Shiite militant group Hezbollah says in 2013 it has deployed fighters to back Syrian government forces.

Iran also boosts its support for Assad.

- US steps back -

On August 21, 2013, a chemical attack on two rebel-held areas near Damascus reportedly kills more than 1,400 people. The regime denies responsibility.

US president Barack Obama pulls back from threatened punitive strikes, instead agreeing a deal with Moscow meant to dismantle Syria's chemical weapons arsenal.

- Islamic State group -

In June 2014, the jihadist Islamic State group (IS) proclaims a "caliphate" over territory it has seized in Syria and Iraq.

In September, a US-led coalition launches air strikes against IS in Syria.

Kurdish groups, which since 2013 have set up autonomous administrations in Kurdish-majority areas, join with Arabs to form the US-backed Syrian Democratic Forces (SDF).

The alliance ousts IS from key areas, including its de facto capital Raqa, in 2017, and then in 2019, the group's last Syrian holdout in the village of Baghuz near the border with Iraq.

- Russia rescues Assad -

In September 2015, Syria's main ally Russia launches air strikes in support of Assad's beleaguered troops, a turning point in the war.

In a string of deadly campaigns, the regime retakes key rebel bastions, from Aleppo in 2016 to Eastern Ghouta on the outskirts of the capital in 2018.

- Chemical attacks -

In April 2017, a sarin gas attack on the rebel-held town of Khan Sheikhun kills more than 80 people.

US President Donald Trump unleashes missile strikes against the regime's Shayrat airbase, from where the gas attack was allegedly launched.

In April 2018, the US, France and Britain launch retaliatory strikes after an alleged regime chemical attack on the then rebel-held town of Douma, near Damascus.

- Turkey offensive against Kurds -

On October 9, 2019, Ankara launches an offensive targeting Kurdish forces in Syria, whom it brands "terrorists" linked to Kurdish insurgents in Turkey.

The operation follows Washington's announcement that US forces would withdraw from the border areas between Turkey and Syria.

The operation allows Turkey to take control of a 120-kilometre-long (75-mile-long), 30-kilometre-wide strip of territory along the border.

- Battle for Idlib -

In December 2019, the regime launches a deadly offensive in northwestern Syria to retake the country's last major jihadist bastion of Idlib.

A ceasefire sponsored by Russia and Turkey is reached in March 2020 after months of bombardment and fighting which have provoked a humanitarian crisis.