US President Donald Trump said the PKK was worse than the Islamic State, noting that Turkish President Recep Tayyip Erdogan's decision to launch an attack in Syria did not surprise him.

Trump said the PKK was more of a terrorist threat than ISIS.

The president said he had asked the Kurds not to release ISIS prisoners, "but they did release some to embarrass us."

"Basically they are not angels," Trump said in response to accusations, especially from his foreign allies, of "abandoning" the Kurds.

"The Kurds are safer now. The Kurds know how to fight. They fought with us, we paid a lot of money to fight with us and that's good."

Trump again defended his decision to withdraw US troops from northeastern Syria. "If Turkey enters Syria, this is an issue between Turkey and Syria. It is not an issue between Turkey and the United States as many stupid people want you to believe," he said. He continued: "We hope that Turkey and Syria settle the matter between them."

Trump questioned why US forces were protecting Syrian territory, noting that if Russia would help protect the Kurds, it was a good thing, not a bad one.

Turkish army and Syrian opposition launched Operation Spring of Peace in northeastern Syria (Getty Images)

Not a surprise
On the Turkish spring peace operation in northeastern Syria, the US president said that "Erdogan's decision to launch an attack in Syria did not surprise me," but Trump returned and stressed that he did not give Turkey the green light to invade Syria, adding that sanctions on Turkey would be destructive if the meeting between His deputy Mike Pence and Erdogan.

He added that it would be better to impose sanctions on the Turkish regime than to push US troops to fight.

"There are many countries that hate IS as much as we hate it. Sometimes more than us," he said, adding that these countries should replace the United States.

"Syria could get help from Russia, no problem," he said sarcastically. "There is a lot of sand there; there are a lot of sand that they can enjoy."

"We are in a very good strategic position. It is wonderful from a strategic point of view," he said, noting that all US soldiers have withdrawn from the area.

"We will help negotiate. We want wars to stop from a humanitarian perspective."