WASHINGTON – Former first lady Michelle Obama on Friday appeared to rebuke President Donald Trump's "go back" language, saying that what "truly makes" America great is diversity.

"What truly makes our country great is its diversity," Obama wrote in a tweet. "I’ve seen that beauty in so many ways over the years. Whether we are born here or seek refuge here, there’s a place for us all.

"We must remember it’s not my America or your America. It’s our America," she concluded.

Obama, who is the most admired woman in the world according to a new poll, did not mention the president by name, but her online posting echoed Trump's trademark tagline: "Make America Great Again."

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The former first lady's tweet came amid a week-long feud between Trump and four Democratic congresswomen of color -- that started after the president criticized the lawmakers on Twitter and called on them to "go back and help fix the totally broken and crime infested places from which they came."

The congresswomen, Reps. Alexandria Ocasio-Cortez, D-N.Y., Ayanna Pressley, D-Mass., Rashida Tlaib, D-Mich., and Ilhan Omar, D-Minn., have been persistent critics of the president and his administration's polilicies since taking office earlier this year. Following Trump's tweet, the congresswomen — who are colloquially known as "The Squad" — criticized Trump's tweet and rhetoric as racist. The House on Tuesday also voted to formally condemn Trump's tweet as racist.

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All four congresswomen are American citizens, and three of them were born in the U.S. Omar immigrated from Somalia to the United States over 20 years ago and is a naturalized U.S. citizen. Omar and Tlaib are the only two Muslim women in the House of Representatives.

The president's rhetoric and attacks on the four women took on a new dimension Wednesday. During a rally in North Carolina, chats of "send her back" erupted after Trump mentioned Omar while riffing about The Squad.

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Despite initially rebuking the chant on Thursday, Trump has since doubled down yet again on his rhetoric about the four Democrats, especially Omar.

While speaking to reporters in the Oval Office Friday, Trump was asked about being unhappy about the chanting when he cut off the reporter.

"No, you know what I’m unhappy with? The fact that a congresswoman can hate our country," Trump said.

He added that the people at his North Carolina rally on Wednesday are "incredible people."

“Those people in North Carolina, that stadium was packed. It was a record crowd and I could have filled it 10 times, as you know,” Trump told reporters. “Those are incredible people. Those are incredible patriots."

"But I’m unhappy when a congresswoman goes and says, ‘I’m going to be the president’s nightmare,'" Trump continued. "She’s going to be the president’s nightmare. She’s lucky to be where she is, let me tell you, and the things that she has said are a disgrace to our country."

Omar was greeted by her supporters with chants of "Welcome home, Ilhan" at the airport in her home state of Minnesota on Thursday evening.

The progressive Democrat said at the airport that "we are going to continue to be a nightmare to this president because his policies are a nightmare to us and we are not deterred, we are not frightened."

Trump several hours after his Oval Office comments re-upped his complaints about Omar and The Squad, adding that he doesn't care if the feud is "good or bad politically."

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"When they call our country garbage, I don't care about politics," he said. "You can't talk this way about our country. Not when I'm the president."

When asked about the congresswomen's First Amendment rights, Trump acknowledged they have free speech rights under the Constitution "but that doesn't mean i'm happy about them saying."

"When they say bad things about us, we can certainly feel -- and again we have First Amendment rights also -- we can certainly feel what and say what we want," Trump said.

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