Ankara: President Recep Tayyip Erdogan vowed Turkey would not allow the US to delay the establishment of a 'safe zone' in northern Syria, in comments published on Thursday.
Ankara and Washington earlier this month agreed after difficult talks to set up a buffer zone between the Turkish border and Syrian areas controlled by the US-backed Kurdish YPG militia.
The NATO allies agreed to set up a joint operations centre which Turkey said at the weekend was at full capacity.
"We will never allow a delay similar to that in Manbij. The process should advance swiftly," Erdogan said, according to CNN Turk broadcaster.
Turkey and the United States in May last year agreed a road map including the withdrawal of the Kurdish People's Protection Units (YPG) from Manbij in northern Syria.
"The agreement made with the US towards clearing the east of the Euphrates (river) from the YPG and setting up a safe zone is the right step," Erdogan said after returning from talks with Russian President Vladimir Putin.
He said the YPG was "pulling a trick in Manbij" and had not withdrawn. Turkey has repeatedly accused the US of delaying the previous deal.
Ankara says the YPG is a "terrorist" offshoot of the outlawed Kurdistan Workers' Party (PKK), which has been waging an insurgency inside Turkey since 1984.
The PKK is blacklisted as a terror group by Ankara, the US and the European Union.
But the US worked closely with the YPG in the fight against the Islamic State (IS) extremist group.
Turkey-US relations have been particularly tense over American support to the YPG but other issues remain, including the failure to extradite a Pennsylvania-based Muslim preacher blamed for the 2016 failed coup in Turkey.
But Erdogan said joint US-Turkey patrols would "start soon" as part of the latest agreement for northern Syria.
He said Turkish forces and armoured vehicles were already at the border, adding: "We are in a position where we can do anything at any moment." Turkey repeatedly threatened to launch a third cross-border offensive in Syria against the YPG until the US-Turkey agreement.
Previous offensives by the Turkish military supporting Syrian rebels took place against IS in 2016 and against the YPG in early 2018.