President Trump told reporters outside the White House on Thursday that he hopes attendees at his evening rally in Cincinnati don't chant about sending members of Congress back to their supposed home countries -- but added that the situation might be beyond his control.

Last month, attendees at a Trump rally in North Carolina began a "send her back" chant directed at Rep. Ilhan Omar, D-Minn. Trump said the next day he disagreed with the chant, and was "not happy with it."

"I don't know that you can stop people," Trump said Thursday. "We'll see what we can do. I'd prefer that they don't. But if they do it, we'll have to make a decision then."

"I don't know that you can stop people."
— President Trump on 'send her back' chants

Even Trump's closest advisers seemed uncertain as to what may transpire.

"If it happened again, he might make an effort to speak out about it," Vice President Mike Pence said recently.

Rep. Steve Chabot, R-Ohio, who represents a Cincinnati-area district, said Wednesday he hopes the crowd will avoid such chants this time, and he thinks Trump will react more quickly if it does happen.

"I would discourage the crowd from doing anything inappropriate and I think saying something like that would be inappropriate," Chabot said. "I would hope that the president would silence the crowd, tell them: 'Hey, don't do that, there's no place for that. It's not helpful, it's not right.'"

In other remarks, Trump slammed the "fake news" for not reporting on the news that a Bill Clinton-appointed federal judge had dismissed a lawsuit by the Democratic National Committee (DNC) against key members of the Trump campaign and WikiLeaks over hacked DNC documents.

Judge John Koeltl, sitting in the Southern District of New York, wrote in an 81-page opinion on Tuesday that the DNC's argument was "entirely divorced" from the factual record in the case.

The judge said the defendants "did not participate in any wrongdoing in obtaining the materials in the first place" and therefore bore no legal liability for disseminating the information.

Trump also commented on news of short-range missile testing by North Korea, saying he wasn't concerned.

"Short-range missiles, we never made an agreement on that. I have no problem. We'll see what happens. But these are short-range missiles, they're very standard," Trump said.

Turning to Wednesday night's Democratic presidential debate, Trump suggested it was a sort of pyrrhic win for former Vice President Joe Biden.

"I think Biden did OK,” Trump said, referring to Biden. “He came limping through, but he got through it.”

Biden ended the debate by issuing a vexing call for supporters visit "Joe 30330" -- leading to confusion as to whether the former vice president was promoting a website, text messaging number, or even the next millennium.

Trump said Sen. Kamala Harris of California, on the other hand, “had a bad night."

TRUMP ANNOUNCES MAJOR NEW TARIFFS ON $300B IN CHINESE GOODS

Earlier Thursday, Trump announced a new round of 10 percent tariffs on China after U.S. representatives returned home from meeting with the Chinese delegation in Shanghai. The news sent the stock market tumbling.

"If they don't want to trade with us anymore, that would be fine with me," Trump told reporters. "It would save a lot of money."

The president said China decided to renegotiate the deal before signing, and had agreed to buy more agricultural products from the U.S. – but has not yet done so.

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The U.S. has already implemented 25 percent tariffs on $250 billion worth of Chinese goods. The new round of tariffs is expected to take effect on Sept. 1. The president has noted on Twitter that this round of tariffs could hit large U.S. corporations like Apple.

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It is expected that U.S. Trade Representative Robert Lighthizer will come up with a list of items that will be subject to the tariffs.

Fox Business' Brittany De Lea, Edward Lawrence, and The Associated Press contributed to this report.