Correction: An earlier version of this story misquoted President Donald Trump regarding the conflict between Turkey and Kurdish fighters in Syria. The president said: “They have a problem with Turkey, they have a problem at a border. It's not our border.”

WASHINGTON – President Donald Trump, facing bipartisan condemnation over Turkey's invasion of Syria, defended his handling of the matter Wednesday as "strategically brilliant" and downplayed the U.S. alliance with the Kurds, who are "not angels," he said.

"They've got to work it out," Trump said in the Oval Office as Vice President Mike Pence and Secretary of State Mike Pompeo prepared to travel to Turkey to try to negotiate a cease-fire and avoid a humanitarian crisis on the Syrian border.

In remarks throughout the day,Trump dismissed mounting criticism from Capitol Hill and allies, questioningthe character of Kurds, many of whom fought alongside U.S. troops against the Islamic State, also known as ISIS.The House overwhelmingly backed a resolution condemning Trump's decision to withdraw U.S. troops from Syria, a move that cleared the way for Turkey's invasion.

Democratic leaders, including House Speaker Nancy Pelosi, stormed out of an afternoon meeting at the White House on Syria, claiming the president does not have a plan to contain the Islamic State. White House spokeswoman Stephanie Grisham described the move as "baffling but not surprising."

Earlier, during an East Room news conference with Italian President Sergio Mattarella, Trump welcomed reports that Russian troops entered regions once occupied by a small number of U.S. special operations forces – a stance that runs counter to the views of many lawmakers who expressed concern about Russia's involvement.

"Frankly, if Russia is going to help the Kurds, that’s a good thing," Trump said.

'Not angels'

Last week, the president tried to diminish the U.S.-Kurd alliance by noting thatthe Kurds had not fought with Allied powers in World War II. Trump said one group of Kurds, the Kurdistan Workers' Party, is "more of a terrorist threat" than the Islamic State.

"They're not angels," Trump said Wednesday.

The United States considers the Kurdistan Workers' Party, or the PKK, a terrorist organization. U.S. troops allied with what Turkey described as an offshoot of that group, the People’s Protection Units, or YPG, to fight the Islamic State in Syria.

Alliance:Trump downplays ties to Kurds: 'They didn't help us in the Second World War'

House action:House will vote on resolution condemning Trump over Syria, Turkey

“They’ve got a lot of sand over there,” Trump said. “There’s a lot of sand that they can play with.”

The president has repeatedly framed his decision in Syria as part of his broader pledge to withdraw U.S. troops from foreign entanglements.

U.S. troops remained in Syria on Wednesday despite Trump’s statement that they’d been withdrawn, according to a U.S. official who was not authorized to speak publicly. The military continues to close outposts in Syria housing U.S. commandos, the official said. The military has concerns for their safety because militias supported by Turkey are viewed as a potential threat in Syria to American troops, who are being evacuated by aircraft and convoys.

It's not clear how many of the 1,000 service members Trump intends to withdraw from Syria will return to the USA versus being redeployed to other countries in the region.

Graham on Trump: 'Outrageously dangerous'

Trump's remarks on Syria drew renewed ire from Sen. Lindsey Graham, R-S.C., who has been a close Trump ally on many issues but critical of the president's Middle East policy.

"What the president said today is just outrageously dangerous,” Graham said. "It undercuts Pence and Pompeo. And I don’t agree with his construct that Turkey's invasion of Syria is of no concern."

Trump blasted Graham during his news conference, noting the South Carolinian's long-held hawkish foreign policy views.

"Lindsey Graham would like to stay in the Middle East for the next 1,000 years," Trump said before suggesting that voters in South Carolina would prefer that their senior senator focus on other issues, such as getting judges confirmed.

Graham quickly fired back.

"With all due respect for the president, I think I'm elected to have a say about our national security that in my view, what is unfolding in Syria is going to be a disaster,” he said on Capitol Hill. "I think this is the biggest mistake of his presidency, and I will not ever be quiet."

Rep. Michael McCaul, R-Texas, the ranking Republican on the House Foreign Affairs Committee, said the fighting in the region created a power vacuum that U.S. geopolitical foes are beginning to exploit.

"This is opening things up to the Russians. They’re literally where we deserted, in our camps,” McCaul said. "It's an opening for Iran, it's an opening to reinvigorate ISIS. … I think the Russians and Iran are going to take over that country."

More than 90 House Republicans introduced legislation Monday that would require the president to impose far-reaching sanctions on Turkey. The legislation, led by Rep. Liz Cheney, R-Wyo., seeks to ban U.S. military transactions with Turkey and would slap economic penalties on Turkish President Recep Tayyip Erdogan and other high-ranking members of his government.

The House voted 354-60 Wednesday to approve a rare bipartisan rebuke of Trump's handling of the situation. Two-thirds of the Republicans joined with the Democrats to support the measure.

Trying to get ahead of congressional action, Trump announced additional sanctions on Turkey on Monday.

The Obama administration entered its alliance with the Kurds hesitantly and faced criticism for doing so. In 2016, Graham, back from a trip to Turkey, described the alliance as "the dumbest idea in the world."

"I just got back from Turkey. They’re not OK with this," he told Defense Secretary Ash Carter and Joint Chiefs of Staff Chair Gen. Joseph Dunford. "They think this is the dumbest idea in the world, and I agree with them."

Since then, U.S. and Kurdish forces captured the territory the Islamic State held in Syria, and Trump has frequently held up maps to tout the progress made in that effort.

Pence and Pompeo are set to travel to Turkey to meet with Erdogan to try to negotiate a cease-fire. Erdogan initially indicated he wouldn’t meet with the U.S. delegation, then expressed a willingness to do so.

Stabilizing force in Syria

During his news conference, Trump rejected criticism that he gave Erdogan a "green light" to invade northern Syria.

"I didn't give him a green light," said Trump, who noted Turkey has long sought to push Kurds they view as a threat back from the border. "Just the opposite of a green light."

Analysts said the U.S. presence in northern Syria stabilized the area, and the post-withdrawal influx of Turkish and Russian troops makes it more dangerous.

Mark Dubowitz, chief executive of the Foundation for Defense of Democracies, described the president's remarks as "yet another ignominious moment in Trump’s treatment of American allies."

This one is "particularly egregious," he said, "given that the Kurds lost 11,000 men and women fighting ISIS and helping save American lives."

Republican strategist Rick Tyler, a Trump critic, agreed.

"Well, I hope they weren't angels, they were killing our enemies," Tyler said. "Trump has shown the world that he is weak, easily manipulated, corrupt and disloyal. We will pay in treasure and blood tomorrow for his misguided ill-informed decisions today."

Contributing: Tom Vanden Brook, Christal Hayes and Maureen Groppe