U.S. President Donald Trump said late Monday that he wasn't "siding with anyone in Syria" with his decision to withdraw troops from the embattled country, while reiterating that had has a "good relationship" with his Turkish counterpart President Recep Tayyip Erdoğan.

Trump's remarks came amid Turkey's efforts to clear northeastern Syria of the People's Protection Units (YPG) terrorists.

"I am not siding with anybody. We've been in Syria for many years. Syria was supposed to be a short-term hit. We were supposed to be in and out," Trump said during a press conference at the White House.

Trump has been facing mounting pressure in Washington after the White House announced late Sunday that the U.S. would pull back its forces in Syria ahead of a "long-planned" Turkish operation.

The Trump administration has ruled out any U.S. support for the operation, and in the face of significant pushback, the president, in a drastic change of tone, vowed "if Turkey does anything that I, in my great and unmatched wisdom, consider to be off limits, I will totally destroy and obliterate the economy of Turkey."

In his remarks, the U.S. president said there were just 50 troops in the area where Ankara was planning to carry out the operation and did not want them to get hurt.

"I think there is a lot of pressure on Turkey. They have been fighting with the PKK for many years," said Trump, adding the former Obama administration started the dispute and "natural war" between Turkey and the PKK, citing reports.