Turkish forces attacked several areas in Syria’s northern Idlib governorate on 1 June, including positions occupied by the US-led coalition, according to local reports.

This is the first time that Ankara’s forces have targeted positions held by its NATO allies in Syria.

The attack came just hours after Turkish President Recep Tayyip Erdogan announced that his troops will proceed with the planned military invasion into Syria, starting with the cities of Tal Rifaat and Manbij.

The operation will allegedly resume efforts to establish a 30-kilometer long ‘safe zone’ along Turkey’s southern borders in order to curb “threats” from the Kurdistan Workers Party (PKK) and the Kurdish People’s Protection Units (YPG) – the backbone of the US-backed Syrian Democratic Forces (SDF) – which Ankara labels as terrorist organizations.

“We are taking a new step in establishing a 30km security zone along our southern border,” the Turkish president said. “We will clean up Tel Rifaat and Manbij.”

Presidential spokesperson Ibrahim Kalin justified the illegal invasion of Syria, saying: “We consult with our allies and other countries. We also cooperate when necessary, but when it comes to our safety, we clearly determine our action based on our priorities and act accordingly, without asking anyone’s permission.”

Kalin urged Russia and the US to stick to agreements made in 2019 regarding regions controlled by Kurdish militant groups.

Turkey says US-backed SDF forces pose a threat to its borders, and in response, Turkish troops have occupied large swathes of northern Syria.

Erdogan’s statement comes just weeks after he announced plans to return one million Syrian refugees to areas under the control of the Turkish army, promising to provide them with houses, schools, hospitals, and even agricultural machinery.

The plan was rejected by the SDF, however, as they step up efforts to rally international support against the threat of the ‘Arabization‘ of northern Syria.

The plan to launch a new military campaign in Syria also comes in the shadow of Erdogan’s refusal to allow Finland and Sweden to join NATO. A unanimous vote among NATO members is required to permit countries to join the western-led military alliance.

Erdogan has said Sweden and Finland must end their support for the PKK and other groups, bar them from organizing events on their territory, extradite those sought by Turkey on terrorism charges, support Ankara’s military and counter-terrorism operations, and lift all arms export restrictions.

Turkish Foreign Minister Mevlut Cavusoglu doubled down on their refusal to approve the NATO membership of the two Nordic countries on 31 May.

On 27 May, Russian forces carried out airstrikes against positions held by Turkish-backed armed groups on the Syrian-Turkish border, for the first time since the start of their operations in Syria.

Further strikes by Russian forces against Turkish-backed rebels took place on 29 May.

An analysis by The Cradle assessed Turkish-Russian relations following the start of the war in Ukraine, which saw Ankara side mostly with Kiev and lean towards the west without burning its bridges with Moscow.