This combination of file pictures shows (L) President of Turkey Recep Tayyip Erdogan deliverling a speech during a meeting in Ankara, on January 26, 2018 and U.S. President Donald Trump (L) looking on during a joint press conference at the White House in Washington, DC, July 30, 2018.(Xihua/AFP)

WASHINGTON, Dec. 14 (Xinhua) -- U.S. President Donald Trump on Friday talked with his Turkish counterpart Recep Tayyip Erdogan over phone on Friday, as unusual war of words has erupted between the two NATO allies over U.S. military presence in Syria.

The two presidents "discussed bilateral issues, including the security concerns of Turkey and the United States in Syria and the fight against terrorism," according to a statement issued by White House Spokesperson Sarah Sanders.

Trump and Erdogan agreed to continue coordinating to "achieve our respective security objectives in Syria," the statement read, without further details about the call.

A separate statement issued earlier by the Turkish presidency noted that during the call, Erdogan expressed Turkey's legitimate concern over the presence and actions of People's Protection Units (YPG) and other Kurdish militias in northern Syria.

Also on Friday, Erdogan said during an international conference in Istanbul that his country has run "out of patience" with the United States over its support for the Kurdish militia in Syria, threatening a renewed military offensive soon and the seizure of the northern Syrian town Manbij if Washington fails to remove the YGP from the area.

"We will no longer tolerate a single day of delay. We are determined to bring peace and security to areas in the east of the Euphrates," he said.

Earlier on Wednesday, Erdogan said Turkish troops will be marching soon into northern Syria to "free the east of the Euphrates from the separatist terrorist organization."

In an unusually harsh response, the Pentagon said hours later on Friday that "unilateral military action into northeast Syria by any party, particularly as U.S. personnel may be present or in the vicinity, is of grave concern. We would find any such actions unacceptable."

"Uncoordinated military operations will undermine that shared interest" of the U.S. and Turkish sides, it added.

Ankara has long regarded the YPG as Syrian affiliate of the Kurdistan Workers' Party that has been designated as a terrorist organization by Turkey, the United States and the European Union, arguing that its presence along Turkey's southern border poses a serious security threat to Ankara.

Turkish and U.S. forces last month started joint patrols in Manbij. In a separate move, U.S. Defense Secretary James Mattis said on Nov. 21 that the U.S. military is building observation posts along the Turkey-Syria border, in an effort widely seen to reduce tension with Turkey.

However, such efforts appeared to have been made in vain after the Turkish Armed Forces fired artillery shells at YPG positions east of the Euphrates in northern Syria last month.

Ankara accused Washington of dragging its feet on implementing a deal brokered with Turkey to clear Kurdish fighters from the small town of Manbij near the Turkish border.