President Donald Trump stepped up his attacks on a quartet of progressive congresswomen of color Monday, accusing them of "hating" the United States and Israel and loving terrorists and saying they should feel free to leave the country if they're not happy here.

"These are people who in my opinion hate our country," Trump said at a "Made in America" event outside the White House.

"All I'm saying is, if they’re not happy here, they can leave. There will be many people who will be happy," Trump said.

Of the four House members Trump has been targeting — Democratic Reps. Ilhan Omar of Minnesota, Alexandria Ocasio-Cortez of New York, Ayanna Pressley of Massachusetts and Rashida Tlaib of Michigan — the president mentioned two by name. He used the most incendiary language in talking about Omar, a naturalized citizen who came to the United States from Somalia as a child.

Trump accused the freshman congresswoman of being somebody who "hates Israel" and "hates Jews, hates Jews. It's very simple."

"I mean, I look at the one, I look at Omar. I mean, I don't know, I never met her, I hear the way she talks about al Qaeda," Trump said. "Al Qaeda has killed many Americans. She said, 'you can hold your chest out, you can, when I think of America, huh, when I think of al Qaeda, I can hold my chest out,'" he said.

It's unclear what comments Trump was referring to, but some conservative news sites have made an issue out of a 2013 interview in which she said her college professor's "shoulders went up" every time he mentioned al Qaeda in a class on terrorism.

Trump also referred to Omar's remarks in March about the Sept. 11, 2001, terrorist attacks and Muslim civil rights, in which she mistakenly said the Council on American-Islamic Relations was founded in response to the terrorist attacks, adding "because they recognized that some people did something" — a phrasing that some in conservative media have interpreted as a flippant reference to the attack.

"When she talked about the World Trade Center being knocked down -- 'some people.' You remember the famous 'some people'?" Trump asked. "These are people that, in my opinion, hate our country."

The president singled out Ocasio-Cortez for helping scuttle Amazon's plans to build a second headquarters in New York. "It's really hurt New York," he said. "That was a terrible thing she did."

Trump first went after the quartet over the weekend, tweeting they should "go back" to the countries they came from, even though three of them are from the United States.

The president's comments have come under fire from Democrats and some Republicans, but Trump continued the harangue Monday.

"These are people that hate our country," he said. "They hate it, I think, with a passion. Now it's possible I'm wrong. The voter will decide. But when I hear the way they talk about our country — when I hear the anti-Semitic language they use, when I hear the hatred they have for Israel — and the love they have for enemies like al Qaeda — then you know what? I will tell you that I do not believe this is good for the Democrat Party."

Asked if he was concerned that his comments were being seen as racist, giving white nationalists a reason to find common cause with him, Trump said, "It doesn’t concern me because many people agree with me. All I’m saying is that if they want to leave, they can leave. It doesn’t say leave forever."

Asked about House Speaker Nancy Pelosi's accusation that his comments about the congresswomen show that his true motives are to "make America white again," Trump said, "That's a very racist statement, I'm surprised she'd say that."

The president was also questioned about the comments by Sen. Lindsey Graham, R-S.C., earlier in the day urging that he "aim higher."

"These are congressmen, what am I supposed to do, just wait for senators?" Trump replied.

Earlier in the day, the president took to Twitter to demand the women apologize to the country for "foul language" and "terrible things they have said."

"When will the Radical Left Congresswomen apologize to our Country, the people of Israel and even to the Office of the President, for the foul language they have used, and the terrible things they have said," Trump tweeted Monday.

"So many people are angry at them & their horrible & disgusting actions!" he added.

When will the Radical Left Congresswomen apologize to our Country, the people of Israel and even to the Office of the President, for the foul language they have used, and the terrible things they have said. So many people are angry at them & their horrible & disgusting actions! — Donald J. Trump (@realDonaldTrump) July 15, 2019

If Democrats want to unite around the foul language & racist hatred spewed from the mouths and actions of these very unpopular & unrepresentative Congresswomen, it will be interesting to see how it plays out. I can tell you that they have made Israel feel abandoned by the U.S. — Donald J. Trump (@realDonaldTrump) July 15, 2019

Even before Trump spoke, Pelosi, D-Calif., said a resolution would be introduced addressing the president's "xenophobic" comments.

A day earlier, Trump touched off an uproar when he tweeted that the group of progressive congresswomen should "go back" and try to fix the "crime infested places" they "originally came from" before telling the U.S. government how to handle its problems.

Then, after his comments were denounced as racist, he doubled down.

"So interesting to see 'Progressive' Democrat Congresswomen, who originally came from countries whose governments are a complete and total catastrophe, the worst, most corrupt and inept anywhere in the world (if they even have a functioning government at all), now loudly and viciously telling the people of the United States, the greatest and most powerful Nation on earth, how our government is to be run," Trump wrote in a series of three tweets.

All four of the congresswomen are people of color, and three of the four were born in the U.S.

Tlaib, a Palestinian American, was born in Michigan; Ocasio-Cortez, who is of Latin American descent, was born in New York; and Pressley, who is African American, was born in Cincinnati.

Omar vowed after Trump's remarks at the White House not to back down in the face of attacks by Trump and conservative media.

They are working to silence the voices of the people who see themselves represented in me. I will stay in the ring, fighting for what is right and will never back down in the face of these attacks. — Ilhan Omar (@IlhanMN) July 15, 2019

After Trump's Monday morning tweets, Ocasio-Cortez hit back as well, tweeting that Trump's language a day earlier was "hallmark language of white supremacists."

"Trump feels comfortable leading the GOP into outright racism, and that should concern all Americans," she wrote.

It’s important to note that the President’s words yday, telling four American Congresswomen of color “go back to your own country,” is hallmark language of white supremacists.



Trump feels comfortable leading the GOP into outright racism, and that should concern all Americans. — Alexandria Ocasio-Cortez (@AOC) July 15, 2019

After arriving on Capitol Hill later Monday morning, Ocasio-Cortez called it "unfortunate" that Trump "feels the way he feels" about people of color and immigrants, adding, "it’s time to move on from him, and it’s time to move on from his conception of an America that we have tried to move past for a long time."

Trump, she said, "relies on racism, division, and anti-immigrant sentiment to consolidate power because he does not have a positive vision for the future of America."

In his latest tweets, Trump may have been responding to remarks two of the congresswomen have made about Israel. In an interview with Jacobin magazine published Saturday, Tlaib said Israel was engaging in "continued dehumanization and racist policies." And earlier this year, Omar was criticized for remarks and tweets she made about Israel and 9/11.

On Sunday, all four quickly responded to the president on Twitter, and other congressional Democrats and several presidential candidates condemned the tweets as well.

Apparently in response, the president tweeted Sunday night that it was "so sad" that Democrats were "sticking up for people who speak so badly of our Country and who, in addition, hate Israel with a true and unbridled passion."