Speaking in Turkey's capital Ankara, President Recep Tayyip Erdogan also emphasised that Turkish troops will move on Manbij and other YPG-held areas in northern Syria after Afrin.
President Recep Tayyip Erdogan said on Friday that Turkey-backed troops had surrounded Afrin city centre in northwestern Syria and were ready to enter at any moment as part of Operation Olive Branch.
"Right now, Afrin city centre is surrounded. We can enter it at any moment," said Erdogan at the inauguration of the governing Justice and Development (AK) Party's Politics Academy in capital Ankara.
"Those who directed Daesh against us yesterday, are today doing the same thing with the Syrian branches of the PKK, the PYD and YPG. When the subject is Turkey, our enemies can become friends in a minute. Closed doors can open, and guns and money can flow abundantly," he said.
TRT World's Shamim Chowdhury reports from inside Afrin.
Eastern side of the Euphrates
Erdogan reiterated Turkey's firm determination to advance to Manbij and other YPG-held locations east of the Euphrates River, once the operation on the Afrin enclave is completed.
"We're in Afrin today. We will be in Manbij tomorrow. The next day we will ensure that the eastern side of the Euphrates River is cleared of the terrorists up to the border with Iraq," Erdogan added.
The US and the YPG terror group, which have been receiving American weapons and support under the pretext of fighting Daesh, are stationed in Manbij and on the eastern side of the Euphrates River.
The US forces in Manbij have recently resisted Turkey's calls for them to leave the area.
The YPG is the Syrian branch of the PKK terror organisation which is responsible for over 40,000 deaths, and has carried out a violent campaign against Turkey for more than 30 years.
It has been listed as a terrorist organisation by Turkey, the US and the European Union.
TRT World 's Defence Analyst Oubai Shahbandar explains what can be Turkey's next move in the region.
Operation Olive Branch
Erdogan also said that a total of 3,171 terrorists have been "neutralised" in Afrin since the start of Operation Olive Branch in northwestern Syria.
Turkish authorities often use the word "neutralised" in their statements to imply the terrorists in question either surrendered or were killed or captured.
On January 20, Turkey launched Operation Olive Branch to clear the PKK-affiliated YPG and Daesh terrorists from Afrin, northwestern Syria.
Since the beginning of the operation, the Turkish military and the Free Syrian Army have cleared more than 159 locations, including five town centres, 124 villages, 30 strategic areas and one YPG base.
Erdogan noted that a total of 815 square kilometres (506 square miles) have been cleared from the terrorists so far.
According to the Turkish General Staff, the operation aims to establish security and stability along Turkey's borders and the region as well as protect Syrians from the oppression and cruelty of terrorists.
The operation is being carried out under the framework of Turkey's rights based on international law, UN Security Council resolutions, its self-defence rights under the UN charter and respect for Syria's territorial integrity, it said.
The military also said only terror targets were being destroyed and "utmost care" was being taken to not harm civilians.
Erdogan said in the initial phase 2,000 square kilometres (772.2 square miles) will be taken into control.
"Then we will ensure security there and send our [displaced] brothers of Afrin back to their homes."