Turkish President Recep Tayyip Erdogan on Friday, December 21 postponed a promised military operation in northern Syria, but warned that the ‘waiting period’ was not open-ended, and Turkey would clear Syria of a Kurdish militia and Islamic State.

“In the next months we will see an operation aimed at removing the YPG and Daesh elements on the ground in Syria,” Erdogan said in Istanbul.

He promised last week to launch a Turkish-led operation before President Donald Trump on Wednesday ordered 2,000 U.S. ground forces to leave Syria.

Erdogan welcomed Trump’s decision but said he remained “cautious” because of “past negative experiences,” referring to Ankara’s continued disappointment over the U.S. administration’s failure to stop providing military support to the People’s Protection Units (YPG), a core component of the Syrian Democratic Forces, the U.S. partner fighting ISIS in north and east Syria.

In November last year, Turkish officials said Trump had promised not to supply weapons to the YPG, although the White House was not as explicit about its intentions. The Pentagon later said it was reviewing military support provided to SDF to make sure it was consistent with previous agreements.

American support for Syrian militias has long been a source of tension between the NATO allies.

The YPG is considered by the Turkish government to be inextricably linked to the outlawed Kurdistan Workers’ Party (PKK), which has waged a decades-long insurgency in Turkey, and is designated as a terror group by Turkey and its Western allies.

But the YPG is not a proscribed organization in the European Union, United Kingdom or United States and it is a key part of the Coalition-backed SDF alliance of Arabs, Christians and Kurds.

The SDF said on Thursday that it will keep fighting ISIS in Syria unless it comes under Turkish attack, after earlier saying that the U.S. pullout would “have a negative impact on the counterterrorism campaign” and allow ISIS to regroup and launch a counterattack.

Also on Thursday, the Pentagon said the U.S. will continue its air campaign against ISIS in Syria as long as American troops are on the ground, but will not “speculate on future operations.”

The U.K. and France have indicated they will continue counter-ISIS operations in Syria.

Trump agreed Syria withdrawal in call with Erdogan

On December 12, Erdogan said Turkey would start an offensive in northern Syria within days, but on December 14, he spoke to Trump on the phone.

According to a Friday article in Turkish newspaper Hurriyet, Trump decided to pull out of Syria during that call with Erdogan and ordered his national security adviser John Bolton to “start the work” to prepare withdrawing troops.

The Associated Press also reported later on Friday that Trump agreed to the withdrawal during the call.

U.S. officials agreed on Tuesday to withdraw the U.S. observation posts along the Syria-Turkey border to show Turkey the American withdrawal was legitimate, and to avoid provoking a Turkish attack on northern Syria while U.S. forces are still present.

Erdogan on Friday said the U.S. decision meant Turkey would “wait a little longer” before launching an operation which would involve Syrian rebels.

“We had decided last week to launch a military incursion … east of the Euphrates river,” he said.

“The phone call we made with Trump, as well as contacts between our diplomats and security officials, and the statements made by the American side led us to wait a little longer,” he added.

“We have postponed our military operation against the east of the Euphrates river until we see on the ground the result of America’s decision to withdraw from Syria,” he said.

“Of course this is not an open ended waiting period,” he warned, adding that Turkey was working on plans to “neutralize Daesh elements” that still exist in Syria.

“Mr. Trump told us during our conversation ‘will you clean Daesh from here?’ We have cleared them and after this, we will clear them. As long as you give us the support in terms of logistics. And have they [the U.S.] started to withdraw? They have,” he added.

Turkey has carried out two military incursions into northern Syria.

Earlier this year, Turkish military forces and Syrian opposition fighters captured the Efrin region from the YPG after a two-month air and ground offensive called Operation Olive Branch. There was no ISIS presence in Efrin.

In 2016, Turkey launched Operation Euphrates Shield to capture ISIS-held territory west of the Euphrates and prevent the SDF from expanding territory it had captured from the jihadists around Manbij, creating a tense front line near the city.

With reporting from AFP