The president’s decision to withdraw US troops from the area was met with horror in Washington, with Republicans and Democrats criticising the step.
The withdrawal effectively allows Ankara to proceed with a long-threatened military offensive against the Kurdish-led Syrian Democratic Forces (SDF).
Mr Trump dismissed concerns about the move.
“The Kurds are fighting for their land....they’re fighting for their land,” he said on Wednesday.
“And as somebody wrote in a very, very powerful article today, they didn’t help us in the Second World War, they didn’t help us with Normandy as an example...they’re there to help us with their land and that’s a different thing,” he said.
The SDF was widely credited for helping the US defeat Isis. The armed coalition of groups lost an estimated 11,000 fighters in the years-long war against the terrorist organisation.
SDF and US forces captured the last piece of Isis held territory in March 2019.
There are now growing concerns that the offensive will means less security around the prisons holding Isis members, as SDF soldiers are redeployed to the border.
Mr Trump claimed the US had helped the Kurdish forces financially.
“We have spent tremendous amounts of money on helping the Kurds in terms of ammunition, in terms of weapons, in terms of money, in terms of pay,” he said.
Mr Trump’s comments about the Kurdish people attracted immediate mockery online.
“The Kurds contributed just as much in Normandy as Donald Trump did in Vietnam,” said Rob Flaherty, the digital director of Beto O’Rourke’s presidential campaign.
“They’ve been fighting teach other for centuries, they’ve been fighting each other for hundreds of years,” Mr Trump said of the two groups.
“We have defeated Isis. We defeated the caliphate,” he added, making no mention of SDF casualties.
“They’re bitter, bitter enemies, have always been, probably always will be.”
Lindsey Graham, a South Carolina senator and close Trump ally, has repeatedly attacked the president for withdrawing troops from northern Syria.
“Pray for our Kurdish allies who have been shamelessly abandoned by the Trump Administration,” he tweeted on Tuesday, as Turkish fighter jets began bombing the region.
Fellow Republicans have also spoken out about the move. Susan Collins, a Maine Republican, said the withdrawal was a “terribly unwise decision.”
Even Nikki Haley, Mr Trump’s former ambassador to the United Nations, called the move a “big mistake” in a tweet.
“The Kurds were instrumental in our successful fight against Isis in Syria. Leaving them to die is a big mistake,” she wrote.
Mr Graham added that the move “ensures the reemergence of Isis” in the Middle East. He is concerned the removal of US troops will create a vacuum, allowing the terrorist group to possibly restore its caliphate.
There are grave concerns that Turkey’s offensive could affected security around Isis prisons and camps, operated by Kurdish fighters.
An estimated 18,000 militants are being held in prisons in the region, including around 60 British citizens.
The president appeared to dismiss these fears and implied that Europe, not the US, would be facing the greater risk from Isis fighters.
“Well [foreign Isis fighters] are going to be escaping to Europe,” he said.
“That’s where they want to go, they want to go back to their homes.
“But Europe didn’t want them from [the US]. We could have given it to them they could have had trials.”
“Reminder that Trump has trashed all the allies who fought with us in Normandy, and also just glibly referred to ISIS terrorists returning to Europe [because] of Trump’s policy,” said Ben Rhodes, Barack Obama’s former deputy national security advisor.
The president has said that Turkey will face economic punishment from the US if it acts against the SDF in an inhumane manner.
“Well, we’re going to have to define [humane] as we go along,” he said.
“We’ll see how [Erdogan] does it.
“He could do it in a soft manner, he could it in a very tough manner. And if he does it unfairly, he’s going to pay a very big economic price.”
The Turkish operation began on Wednesday.
Sara, a Syrian Kurd in Tal Abyad, who asked to remain anonymous, previously told The Independent the Kurdish population was particularly concerned that people would be targeted for their ethnicity by the Turkish forces.
“Residents are extremely scared. The air is full of tension. Children are crying and the parents are helpless,” she said.
“The town is on high alert. People here are afraid of a possible genocide by the Turkish enemy. It is disastrous.”