President Recep Tayyip Erdogan has said Turkey will target Kurdish armed groups in two northern Syrian cities in an upcoming military operation.

“We are taking another step in establishing a 30-kilometre security zone along our southern border. We will clean up Tal Rifaat and Manbij of terrorists”, he told a meeting of his ruling party in parliament.

Erdogan said Turkish forces would then proceed, “step by step, into other regions”.

The two cities, lying west of the Euphrates River, are controlled by the Syrian Kurdish armed group, the People’s Protection Units (YPG).

Ankara considers the YPG a “terrorist” group and says it is linked to domestic armed fighters belonging to the Kurdistan Workers’ Party (PKK), which Turkey has also designated as a “terrorist” organisation. The PKK has waged an armed uprising against Turkey since 1984, and tens of thousands of people have died in the conflict.

The Turkish government has accused the YPG of attacking Turkish security forces in Syria.

“We will see who supports the legitimate security operations carried out by Turkey and who tries to oppose them,” said Erdogan.

US Secretary of State Antony Blinken warned Turkey against a new military operation and urged Ankara to stick to cease-fire lines established in 2019.

“It’s something that we would oppose,” Blinken told a joint news conference with NATO Secretary-General Jens Stoltenberg.

“The concern that we have is that any new offensive would undermine regional stability (and) provide malign actors with opportunities to exploit instability,” Blinken said.

Turkey has launched three military operations into northern Syria since 2016, seizing areas along the border in what it says is a bid to secure its frontier from threats from ISIL (ISIS) and the YPG.

The YPG-linked Syrian Democratic Forces (SDF) warned that a military operation by Ankara would undermine efforts to combat fighters from the ISIS (ISIL) armed group in northeastern Syria.

“The SDF has been expecting a possible battle for a while now,” said Farhad Shami, a spokesperson for the Kurdish-led force.

“In the event of an attack, we will pause our war against the Islamic State group [ISIL] and start military measures against the Turkish invasion,” he told the AFP news agency.

Expanding ‘safe zone’

Erdogan said over the weekend that Turkey would not wait for permission from the United States before launching such an operation.

Erdogan on Tuesday told Russian President Vladimir Putin that a 2019 agreement signed between the two countries allowed for the creation of a security zone along the Turkish-Syrian border.

“Its creation is imperative,” Erdogan said.

He has also opposed the recent applications of Finland and Sweden for NATO membership, over what Turkey considers their leniency toward Kurdish armed groups.

The president doubled down on his objections on Wednesday and said Turkey would not change its stance on the Swedish and Finnish NATO application without seeing “binding documents” demonstrating a hardened approach to those Ankara considers “terrorists”.

Both Manbij and Tal Rifaat host large Kurdish populations and lie near Turkey’s border with Syria.

Their capture would allow Erdogan to expand and deepen the so-called “safe zone” along the border where Ankara hopes to resettle Syrian refugees.

But according to Rami Abdul Rahman, the head of the Syrian Observatory for Human Rights, which monitors violence in Syria, the Turkish operation could trigger a new wave of displacements.

More than 100,000 people were displaced from the town of Afrin alone during the 2018 Turkish operation, according to United Nations estimates. Most of the people went east to Tal Rifaat.