Turkey's involvement in the Syrian civil war began diplomatically and later escalated militarily. Initially, Turkey condemned the Syrian government at the outbreak of civil unrest in Syria during the spring of 2011; the Turkish government's involvement gradually evolved into military assistance for the Free Syrian Army in July 2011, border clashes in 2012, and direct military interventions in 2016–17, in 2018, in 2019, 2020, and in 2022. The military operations have resulted in the Turkish occupation of northern Syria since August 2016.
After a decade of relatively friendly relations with Syria from 2000 to 2010, Turkey condemned Syrian president Bashar al-Assad over the violent crackdown on protests in 2011 and later that year joined a number of other countries demanding his resignation. From the beginning of the war, Turkey trained defectors of the Syrian Army in its territory under the supervision of the Turkish National Intelligence Organisation (MİT), among whom emerged the Free Syrian Army (FSA) in July 2011. In May 2012, the Turkish National Intelligence Organisation (MİT) began arming and training the FSA and provided them with a base of operations. Tensions between Syria and Turkey significantly worsened after Syrian forces shot down a Turkish fighter jet in June 2012, and border clashes erupted in October 2012. On 24 August 2016, the Turkish Armed Forces began a direct military intervention into Syria by declaring Operation Euphrates Shield, mainly targeting the Islamic State of Iraq and the Levant.
Turkey has strongly supported Syrian dissidents. Syrian opposition activists convened in Istanbul in May 2011 to discuss regime change, and Turkey hosted the head of the Free Syrian Army, Colonel Riad al-Asaad. Turkey became increasingly hostile to the Assad government's policies and encouraged reconciliation among dissident factions. Turkish President Recep Tayyip Erdoğan declared his intent to "cultivate a favorable relationship with whatever government would take the place of Assad." In 2017, it facilitated the establishment of the Syrian National Army of the Syrian Interim Government, which it finances.
A study by Metropoll in September 2019 found that 68% of Turks disapprove of the current government policies on Syria. The poll also found that 47.5% of Turks see the Free Syrian Army as an "enemy". Three out of four Turks said that Syrian refugees should return to Syria "even if the war continues". According to another research by Metropoll, the amount of support for 2019 Turkish offensive into north-eastern Syria was at 79%, while Operation Olive Branch had 71% support.
Background
Before the Turkish government condemned the actions of the Syrian government after the outbreak of the civil war in 2011, the two countries had a rather good bond from the beginning of the 21st century. This bond could even be referred to as a close alliance.
Since the Justice and Development Party (or the AKP) was chosen as the ruling party in Turkey in 2002, it took a new direction in its policy in Middle eastern relations, which led to an improvement of the relations between Syria and Turkey. The normalization of relations started in late 2004, when the Turkish Prime Minister Recep Tayyip Erdoğan flew to Damascus to sign a free trade agreement. Moving away from a mainly Western oriented policy, towards a geopolitical strategy aiming to become the regional power. Turkey wanted to change the idea that all the neighboring countries were its enemies. This more 'liberal' approach towards neighboring countries could be seen in Syria by the open border-policies, and more dialogue between the countries, for example on cultural and civil-society levels.
Turkey and anti-government forces in Syria
At the beginning of the Syrian Civil War, Turkey trained defectors of the Syrian Army on its territory, and in July 2011, a group of them announced the birth of the Free Syrian Army, under the supervision of Turkish intelligence. In October 2011, Turkey began sheltering the Free Syrian Army, offering the group a safe zone and a base of operations. Together with Saudi Arabia and Qatar, Turkey has also provided the rebels with arms and other military equipment.
On 22 June 2012, a Turkish McDonnell Douglas RF-4E Phantom II reconnaissance jet was intercepted and shot down by the Syrian Army in international airspace and greatly escalated the tensions between the two countries.