US and Turkey at odds over US withdrawal from Syria, as Erdogan refuses sit-down with Bolton The fate of America's Kurdish allies in Syria hangs in the balance.

Despite a high-profile visit by U.S. officials to Turkey this week, the two nations remain at odds over the withdrawal of U.S. forces from Syria, specifically the implications for America's Kurdish allies in Syria.

The public spat comes nearly three weeks after President Donald Trump's surprise announcement that he would pull approximately 2,000 U.S. troops out of northeastern Syria.

Turkish President Recep Tayyip Erdogan rebuffed National Security Adviser John Bolton on Tuesday, refusing a meeting and expressing frustration in the messaging from Bolton and others that Erdogan says differs from what he said was a deal with Trump, signaling he'd prefer to communicate with the president instead.

It was a December phone call between Trump and Erdogan that precipitated the U.S. decision to withdraw U.S. forces, originally within 30 days. U.S. officials later indicated the withdrawal could be done over the course of several months, but now, Bolton, along with officials at the State Department and Pentagon, have said that there is no timeline because a withdrawal is conditions-based.

"Despite the fact that we reached a clear agreement with Mr. Trump, different voices have been raised from different echelons of the U.S. administration," Erdogan said during a speech on Tuesday, adding that he could soon hold another phone call with the American president, according to the Associated Press.

Erdogan said that, during the December call, he told Trump that Turkey would take on the remaining ISIS fighters in Syria after the U.S. withdrew, but that there was no mention of the Kurds -- who have been valuable U.S. partners in the fight against ISIS, but are viewed as terrorists by Ankara, which has routinely threatened to target them.

Over the last week, Bolton and Secretary of State Mike Pompeo have said that ensuring the safety of the Kurds is one of a handful of conditions for a U.S. withdrawal, along with the enduring defeat of ISIS.

U.S. officials told reporters traveling with Bolton overseas that it is Trump's belief that Erdogan already committed to protecting the Kurds. But there was no evidence that Ankara received that message or has given new assurances, with Erdogan saying on Tuesday that U.S. demands are a "serious mistake" and that Turkey "cannot make any concessions."

"Those involved in a terror corridor will receive the necessary punishment," Erdogan said, adding that preparations for a new military offensive in Syria are "to a large extent" complete.

Following the meeting between Bolton and his Turkish counterpart, Erdogan's spokesperson Ibrahim Kalin told reporters there was no slowdown in the timetable for a U.S. withdrawal from Syria and that the U.S. told the Turks it could take place "within 120 days."

Asked about a timetable for withdrawal, Department of Defense spokesperson Cmdr. Sean Robertson told ABC News, "The U.S. will continue to provide support to the Coalition's operation in Syria while withdrawing troops in a strong, deliberate and coordinated manner in order to ensure US forces' safety and protection."

He said the U.S.-led coalition against ISIS "has an approved framework for the withdrawal of forces from Syria, and is now engaged in executing that framework. That framework is conditions-based and will not subject troop withdrawal to an arbitrary timeline."

"Out of concern for operational security, we will not be discussing specific troop movements or timelines, but we do expect to provide a periodic update on progress regarding percentages of equipment removed from Syria," Robertson said, adding, "We will continue to fight to achieve an enduring defeat of ISIS."

Trump declared in December that ISIS had been defeated, saying, "Our boys, our young women, our men -- they're all coming back, and they're coming back now."

Amid reports about the changing timeline for withdrawal, the president tweeted on Monday: "No different from my original statements, we will be leaving at a proper pace while at the same time continuing to fight ISIS and doing all else that is prudent and necessary!"