The decision came after a phone conversation between US President Donald Trump and his Turkish counterpart Recep Tayyip Erdogan on Sunday.
“Turkey will soon be moving forward with its long-planned operation into northern Syria,” the White House said in a statement.
On Monday, Erdogan spoke of imminent army perations against Kurdish militants in Syria.
“There is a phrase that we always say: we can come any night without warning. It is absolutely out of the question for us to further tolerate the threats from these terrorist groups,” Erdogan told reporters.
Ankara views US-backed YPG militants as terrorists affiliated with the homegrown Kurdistan Workers Party (PKK) militant group.
Turkey said it was ready to carry out an air and ground operation to push back YPG militants from border areas after a deadline to jointly establish a so-called safe zone with the US passed.
On the issue of Daesh prisoners in the region, Erdogan said he would work with European states to resolve the issue.
“There are (Daesh prisoners) from France, Germany, other countries. They say ‘We don’t want to have control over them.’ We can’t look after them. What can be done about this? They are going to work on that and I instructed our colleagues to work on that too,” he noted.
Washington has said that Ankara would be responsible for the Daesh militants captured in the area over the past two years.
The White House said US troops would withdraw from the border between Turkey and Syria and wouldn’t be involved in the offensive.
Late last year, Washington stopped a Turkish offensive against Kurdish militants after Trump announced a plan to withdraw troops from Syria.
Trump told Erdogan in their December 14 phone conversation that the US was “done” with Syria and that “it’s all yours.”
British daily The Guardian said on Monday moving US forces out of the area “will in effect abandon Washington’s longtime allies, the Kurds.”
“Allowing Turkey to move into northern Syria is one of the most destabilizing moves we can do in the Middle East. The Kurds will never trust America again,” Ruben Gallego, an Iraq war veteran and Democratic congressman from Arizona, tweeted.
Kurds slam Washington
The so-called Syrian Democratic Forces (SDF) of Kurdish militants said on Monday morning that their US partners had already begun withdrawing troops from areas along Turkey’s border.
Footage aired on Kurdish news agency Hawar purportedly showed US armored vehicles leaving positions near the towns of Ras al-Ayn and Tal Abyad in the border region.
“The American forces did not fulfill their commitments and withdrew their forces from the border areas with Turkey, and Turkey is now preparing for an invasion operation of northern and eastern Syria,” the SDF, which holds much of the area, said in a statement.
SDF spokesman Mustafa Bali accused the US of leaving the area to “turn into a war zone,” adding that the SDF would “defend northeast Syria at all costs.”
Ras al-Ayn residents protest against Turkish operationDemonstrators picketed the US International Coalition Base near the village of Tel Arqam in northern Syria on Sunday over fears of a Turkish offensive on Kurdish-controlled territory.
In August, the US and Turkey agreed to set up the so-called safe zone to the east of the Euphrates River between the Turkish border and Syrian areas controlled by US-backed militants.
Erdogan had given the US until the end of September to come up with concrete results on the development of the zone.
The two sides are reportedly at odds over the depth of the militant-free buffer zone and who should control it.
Turkey expects the creation of a 32-kilometer (20-mile) safe zone in northern Syria, and has stressed that it wants the US-backed YPG cleared from the region.
Syria has reiterated its rejection of the so-called safe area, and dismissed all projects aimed at undermining the unity and territorial integrity of the country.
Turkey set to begin offensive
Commenting on the White House statement on the imminent offensive, Turkey’s Foreign Minister Mevlut Cavusoglu said on Monday that his country was determined to clear its border with Syria of militants.
He claimed that Turkey’s plan does not violate Syria’s territorial integrity.
“Since the beginning of the crisis in Syria, we have supported the country’s territorial integrity, and we will continue to do so from now on,” Cavusoglu said in a tweet.
Ankara says it wants to settle up to two million Syrian refugees in the “safe zone.” State broadcaster TRT Haber said last month that Turkey planned to build towns within the zone at a cost of $27 billion.
Ankara’s official Gazette reported on Friday that Turkey’s Gaziantep University would open three faculties in small towns in northern Syria.
UN voices concern
The United Nations has also said that it is “preparing for the worst” in northeast Syria, stressing that there are “a lot of unanswered questions” about the consequences of the operation.
“We don’t know what is going to happen… we are preparing for the worst,” the UN’s humanitarian coordinator for Syria, Panos Moumtzis, said in Geneva.