The attendees - the leaders of France, Germany, Turkey and Russian Federation - notably "reaffirmed their strong commitment to the sovereignty, independence, unity and territorial integrity of the Syrian Arab Republic" in a joint statement, which many observers saw as a not-so-subtle acknowledgement of the victory of Syrian President Bashar Assad, widely accused of war crimes. The US considers the PKK a terrorist organization, but not the YPG or SDF.
The Manbij deal between Turkey and the United States focuses on the withdrawal of YPG/PKK terrorists from the city to stabilise the region, which is in the northeast of northern Syria's Aleppo province.
President Recep Tayyip Erdoğan and his US counterpart Donald Trump discussed bilateral ties and the latest developments in Syria, including the Manbij road map and Idlib, in a phone call on Thursday, Turkey's presidential press office said Thursday.
Two US military officials confirmed that the Turkish military had shelled SDF positions in northern Syria in recent days. USA support for the Kurdish-led forces has resulted in increased tension between Washington and Ankara.
Although Ankara considers the Kurdish People's Protection Units (YPG) an extension of the terrorist Kurdistan Workers' Party (PKK), Turkey's North Atlantic Treaty Organisation ally the United States continues to support the Kurdish fighters in the fight against the Islamic State (ISIS).
Last week, IS jihadists staged a counterattack following a weeks-long SDF offensive in the countryside around Hajin. This assault has already forced Kurdish forces to retreat across the Euphrates river.
The tensions along the border between US-backed forces and Turkey come despite Washington and Ankara agreeing in June to a "roadmap" to ease tensions around the northern Syrian town of Manbij.
CNN-Turk television quoted Turkish Defense Minister Hulusi Akar as saying that training for the joint patrols between the Turks and the Americans have ended but it was not clear yet when the patrols will start.
The SDF responded on Wednesday with retaliatory artillery and machine gun fire, an SDF spokesperson told Syria Direct, resulting in the destruction of one Turkish military vehicle as well as a border post near Abu Salim, a village west of Kobane.
Turkish and U.S. troops patrolled around the Saju Stream, which separates the Manbij frontline from the city of Jarabulus, an area falling under Turkey's Operation Euphrates Shield, according to media on the ground.
Asked to respond to Erdogan's complaint that the U.S. supports IS, a State Department official responded, "We have been abundantly clear by our words and actions that the US-led Global Coalition is in Syria to defeat [IS] and to support stabilization activities so people can safely and voluntarily return home to help ensure that the defeat of [IS] is enduring".