Syria's war: A timeline of events since 2011

As fresh fighting unthawed the frozen front lines of Syria's civil war in recent days and insurgents seized control of large areas of the country's north, the world's attention is once again on the 13-year war between the government of President Bashar Al Assad and myriad rebel groups. The war was initially sparked by pro-democracy demonstrations in the southern city of Deraa in response to the arrest and torture of teenagers who had painted revolutionary slogans on a school wall. Mr Al Assad government's crackdown on the protests calling for reform and the release of political prisoners gave rise to nationwide demonstrations that soon escalated into a complex civil war that claimed more than 300,000 lives and displaced millions. As the government pressed the military to quell dissent, a coalition of rebel groups were formed to overthrow Mr Al Assad's regime. Over the years, the turmoil turned into a protracted civil war with a head-spinning mix of domestic and international actors, including extremist factions, regional armies and global superpowers, plunging into the chaotic conflict. As Syria surges back into a war with the resurgence of the militant forces that have made territorial gains in Aleppo and Idlib after almost a decade, we look at the key events that shaped the conflict since 2011. March: Violence erupts in Syria's southern city of Deraa after police arrest and torture a group of teens for writing political graffiti against President Bashar Al Assad. Peaceful anti-government protests flare up in several cities around Syria. August: The UN estimates that more than 2,200 people had been killed by Syrian security forces in the first five months of the conflict. The Syrian National Council formed in Istanbul, claiming to be official Syrian opposition. November: Syria is suspended from the Arab League after rejecting a peace plan presented by the group. Coalition of opposition groups under the banner of the Free Syrian Army begins attacks on the armed forces in Damascus and Aleppo. February: The Syrian army begins an assault which killed hundreds of people in just days in the city of Homs, an opposition stronghold and centre of the protest movement. A siege focusing on the Old City lasted three years and the government would not regain control of the city, referred to as the "capital of the revolution" until 2015. March: Syria agrees to UN-backed peace plan that would have seen heavy weapons and troops pulled back from civilian areas, daily pauses in fighting for humanitarian purposes and the release of those imprisoned during the uprising. June: Head of the UN's Department of Peacekeeping Operations, Herve Ladsous, calls the conflict a civil war for the first time. The International Committee of the Red Cross says the same in July. August: The UN formally ends its monitoring mission in Syria after the collapse of the peace plan. November: Syrian opposition leaders announce the formation of a new Syrian opposition coalition, called the National Coalition for Syrian Revolutionary and Opposition Forces, also called the Syrian National Coalition. March: Thousands of fighters belonging to the Iran-backed Lebanese militant group Hezbollah join the war to support the Syrian government and extremist groups begin to rise to prominence in the power vacuum left by fighting. August: US President Barack Obama announces limited military action against targets in Syria in response to the Assad regime’s alleged use of chemical weapons against opposition forces and citizens. November: UN estimates that more than 100,000 people have been killed since the start of the conflict. December: Syria begins dismantling its chemical weapons programme, including the destruction of missile warheads and bombs. July 2014: ISIS declares itself a caliphate with Abu Bakr Al Baghdadi as its leader after making significant territorial gains in Iraq and Syria. September 2014: The US and a coalition of Arab countries expand their air campaign against ISIS in Syria and Iraq. September 2015: Russia carries out its first air strikes in Syria on behalf of the Syrian regime, in what would become heavy involvement in the conflict. December 2016: The Syrian government declares victory in Aleppo after the last rebel fighters are evacuated from the city. October 2017: The Syrian Democratic Forces, a US-aligned Kurdish group, announces that Raqqa has been liberated from ISIS. July 2018: Syrian government forces successfully capture the provinces of Deraa and Al Quneitra after rebels surrender in exchange for safe passage to the province of Idlib. September 2018: Russia and Turkey announce the creation of a demilitarised zone in Syria’s Idlib province. October 2019: US president Donald Trump announces US will leave north-eastern Syria, plunging the region into chaos. Turkey launches an offensive into the Kurdish region of north-eastern Syria. March 2020: Turkey and Russia announce a ceasefire in Idlib, Syria's last opposition enclave, agreeing to establish a security corridor with joint patrols. Covid-19 slows the conflict, hardening front lines of the conflict. May 2021: Mr Al Assad is re-elected. February 2022: Russia invades Ukraine, and its assistance to Syria begins to wane. February 2023 : A huge earthquake kills up to 8,000 people in Syria and eight million were affected. Mr Al Assad allows aid to reach rebel-held areas. December 2024: Extremist group Hayat Tahrir Al Sham makes a surprise attack on Syria's second city, Aleppo, taking large parts of the city.

Syria's war: A timeline of events since 2011

Militants have launched renewed insurgency, taking over large parts of territory in Aleppo and Idlib