2012–2013 escalation of the Syrian civil war

The 2012–2013 escalation of the Syrian Civil War refers to the third phase of the Syrian Civil War, which gradually escalated from a UN-mediated cease fire attempt during April–May 2012 and deteriorated into radical violence, escalating the conflict level to a full-fledged civil war.

Following the Houla massacre of 25 May 2012, in which 108 people were summarily executed, and the subsequent Free Syrian Army (FSA) ultimatum to the Syrian Ba'athist government, the ceasefire practically collapsed as the FSA began nationwide offensives against government troops. On 1 June 2012, President Bashar al-Assad vowed to crush the anti-government uprising. On 12 June 2012, the UN for the first time officially proclaimed Syria to be in a state of civil war. The conflict began moving into the two largest cities, Aleppo and Damascus.

Following the failure of another ceasefire in October 2012, during the winter of 2012–2013 and early spring of 2013 the rebels continued advances on all fronts. In mid-December 2012, American officials said that the Syrian military began firing Scud ballistic missiles at rebel positions in Syria. On 11 January 2013, Islamist groups, including the al-Nusra Front, took full control of the Taftanaz air base in the Idlib Governorate, after weeks of fighting. In mid-January 2013, as clashes re-erupted between rebels and Kurdish forces in Ras al-Ayn, YPG forces moved to expel government forces from oil-rich areas in the Hasakah Governorate. By 6 March 2013, the rebels had captured the city of Raqqa, making it the first provincial capital to be lost by the Assad government. In early April 2013, having expanded into Syria, one of the strongest jihadist insurgent groups, the Islamic State of Iraq, adopted the new name ad-Dawlah al-Islāmiyah fī 'l-ʿIrāq wa-sh-Shām (الدولة الإسلامية في العراق والشام), variously translated as "Islamic State of Iraq and al-Sham", "Islamic State of Iraq and Syria" (both abbreviated as ISIS), or "Islamic State of Iraq and the Levant" (abbreviated as ISIL).

The rebel advances were finally stopped in April 2013, as the Syrian Arab Army reorganized and then initiated offensives. On 17 April 2013, government forces breached a six-month rebel blockade on the Wadi Deif base near Idlib. Heavy fighting was reported around the town of Babuleen after government troops attempt to secure control of a main highway leading to Aleppo. The break in the siege also allowed government forces to resupply two major military bases in the region which had been relying on sporadic airdrops. In April 2013, government and Hezbollah forces, who have increasingly become involved in the fighting, launched an offensive to capture areas near al-Qusayr. On 21 April, pro-Assad forces captured the towns of Burhaniya, Saqraja and al-Radwaniya near the Lebanon–Syria border.

From July 2013, the situation became a stalemate, with fighting continuing on all fronts between various factions with numerous casualties, but without major territorial changes. On 28 June 2013, rebel forces captured a major military checkpoint in the southern city of Daraa. Shortly after, some Syrian rebel groups declared war on the Islamic State of Iraq and the Levant which was becoming increasingly dominant. A major advance took place on 6 August 2013, as rebels and ISIL captured Menagh Military Airbase after a 10-month siege. On 21 August a chemical attack took place in the Ghouta region of the Damascus countryside, leading to thousands of casualties and several hundred dead in the opposition-held stronghold. The attack was followed by a military offensive by government forces into the area. The attack, largely attributed to Assad forces, caused the international community to seek the chemical disarmament of the Syrian Army.

Late 2013 was marked by increased initiative on the part of the Syrian Army, which led offensives against opposition groups on several fronts. The Syrian Army along with its allies, Hezbollah and the al-Abas brigade, launched an offensive on Damascus and Aleppo in November. Fighting between Kurdish forces, rebels and al-Nusra front continued in other locations.