Asked at a White House photo op with Italy's president, "Are you OK -- are you OK with Erdoğan saying that he is not going to do a ceasefire?" -- referring to Turkey's President Recep Tayyip Erdogan's response to U.S. efforts to broker a stop to the conflict -- Trump, after a lengthy discourse about why the U.S. should not be involved in the fighting, then said, "So, if Russia wants to get involved with the -- with Syria, that's really up to them. They have a problem with Turkey, they have a problem at a border. It's not our border. We shouldn't be losing lives over it."
The comment comes amid a torrent of criticism, including among Republicans, of Trump's decision to pull back U.S. troops ahead of a Turkish operation against U.S.-backed Syrian Kurdish forces and now to withdraw nearly all American forces from the war-torn country.
Instead, Trump has called for a ceasefire and peace settlement, dispatching Vice President Mike Pence, Secretary of State Mike Pompeo and National Security Adviser Robert O'Brien to Ankara to meet Turkish officials.
But Erdogan made clear again Wednesday he has no interest in "sitting at a table with a terrorist organization... We're not looking for a mediator or anything, we don't need it," he told Turkish Parliament in a speech.
Erdogan declined to meet with O'Brien, who arrived Wednesday in Ankara and met with Turkey's foreign minister. On Thursday, Erdogan will meet with Pence and Pompeo, who depart from Washington Wednesday, according to Erdogan's communications director.
Despite Erdogan's comments, Trump denied that Erdogan didn't want a ceasefire, saying while seated next to Italian President Sergio Mattarella, "We're trying to get Turkey to do the right thing. We want to get wars stopped."
Turkey launched an offensive against the Syrian Kurdish forces that the U.S. armed and fought alongside against ISIS, but that Turkey considers a terrorist organization. U.S. officials have denied that the administration has abandoned those Kurdish forces, saying the decision to move troops was "tactical" -- or what Trump called "strategically brilliant" Wednesday.
While a senior administration official told reporters Tuesday that the U.S. still supports Syrian Kurdish forces and does not consider them terrorists, Trump badmouthed them Wednesday, saying, "They're not angels."
"It is time for us to go home," the president said. While Russian and Syrian forces loyal to dictator Bashar al Assad moved into towns and bases once held by U.S. troops, Trump dismissed concern over it: "If Russia wants to get involved in Syria, that's really up to them."
At a later news conference, Trump again defended his decision to abruptly withdraw U.S. military forces from northeastern Syria, insisting he wasn't surprised and didn’t give Turkey "a green light" to launch a military operation, calling a reporter's suggestion he did "so deceptive."
"When you make a statement like that, it's so deceptive. Just the opposite of a green light," Trump said. "First of all, we had virtually no soldiers there. They were mostly gone, just a tiny little group. They would have been in harm's way. You have a massive army on the other side of the border. I didn't give them a green light. And If anybody saw the letter, and i can certainly release it, I wrote a letter right after that conversation, a very powerful letter. They've been fighting for many, many years. When you ask a question like that, it's very deceptive."
The president was meeting with congressional leaders Wednesday on the Syria situation -- many of them, including prominent Republicans -- angry about his handling of the situation.
"My goodness, the lack of preparation and thinking about how we could have transitioned to a setting where we can protect the Kurds and also hopefully meet Turkey’s needs and interests — that's something we should have considered a long time ago before we pulled our troops out," Sen. Mitt Romney, R-Utah, said Wednesday.
"But now, to go over and say let's talk to Erdogan is like, 'Hey guys, you let the horses out of the barn. This is, this is too late to be talking about locking the barn door," he added.
GOP Sen. Marco Rubio echoed Romney’s exasperation.
"Frankly, I don’t know what we can do at this point to reverse some of the long-term damage," Rubio said.
Rubio said he fears Erdogan is planning an ethnic cleansing of the Kurds. "This is a really problematic situation that’s unfolding."
GOP Sen. Lindsey Graham also blasted Erdogan for saying sanctions don’t matter and that he will refuse any ceasefire.
"We’re going to sanction that hell out of Turkey. We're going to break their economy until they leave Syria. This is a defining moment of Trump's presidency. If we abandon the Kurds, it will be to our shame and our national security detriment and Trump will own the reemergence of ISIS," Graham said.
Just ahead of the meeting, the House overwhelmingly voted, 354-60, to pass a non-binding joint resolution opposing President Trump’s actions in Syria and condemning his decision to withdraw U.S. troops from northeastern Syria.
ABC News' Benjamin Siegel contributed to this report.