Speaking ahead of a phone call with his Russian counterpart Vladimir Putin, Turkish President Recep Tayyip Erdoğan on Friday called the ongoing conflict in Syria’s rebel-held Idlib “a war.”

“I can say that there is a war,” the president told reporters. “This phone call will determine the course of events. This cruelty will stop.”

German Chancellor Angela Merkel and French President Emmanuel Macron have invited Putin to a “very resolute ceasefire in Idlib,” Erdoğan said. “I cannot say that there is an expected response yet.”

Fighting in Idlib has intensified since the beginning of this year after Russia-backed Syrian government forces launched an offensive in the province in April, saying Turkey failed to uphold its end of a 2018 deal with Russia to remove jihadist fighters from the region.

Talks to reach a compromise between Turkey and Russia in the last two weeks have not been fruitful, while Syrian government forces have killed at least 13 Turkish soldiers in February and close to one million people have fled towards the Turkish border.

Merkel and Macron have proposed to hold a quadruple summit in Istanbul on March 5, Erdoğan told reporters, but Putin “has not given them the desired response on the proposal yet.”

Erdoğan said Turkey will remain in Idlib until Syrian government forces “end their cruelty against the people of Idlib.”

Turkish forces have killed 150 regime fighters and destroyed 12 tanks, 14 artilleries, three armoured vehicles and two pick-up trucks fitted with DHSK guns, Erdoğan announced.

The 25 million Euros ($ 27 million) of aid that Merkel promised Turkey has not arrived yet, the president said, while voicing concerns over the people approaching the Turkish border.

Earlier on Friday, Turkey’s Defence Minister Hulusi Akar, Chief of General Staff General Yaşar Güler and Land Forces Commander Ümit Dündar visited troops in the Hatay province on the Turkish border with Idlib, state-run Anadolu Agency reported.

Erdoğan said he had told the United States that Turkey could have used U.S.-made Patriot missile systems alongside the S-400 systems it purchased from Russia. "We do not want to work in a monotone way," the president said, but the United States “did not, could not give (Turkey) a positive answer.”

The S-400 crisis resulted in the United States removing Turkey from the F-35 stealth fighter program last year, as well as lasting tensions with NATO. Turkey continues efforts to activate the system, Akar said on Thursday.