Prime Minister Justin Trudeau today denounced tweets sent by U.S. President Donald Trump over the weekend that told a series of first-term congresswomen of diverse ethnic backgrounds to "go back" to their countries of origin rather than tell U.S. politicians how America should be governed.

Trump's tweets on Sunday ignited a political firestorm in the U.S. and have been widely denounced as racist, as only one of the four Democrats he targeted — frequent critics of Trump who have called for his impeachment — was born outside the U.S.

Rather than apologize, Trump said Monday that Representatives Alexandria Ocasio-Cortez of New York, Ilhan Omar of Minnesota, Rashida Tlaib of Michigan and Ayanna S. Pressley of Massachusetts should instead apologize to him, the United States and Israel for what he claimed was their "foul language & racist hatred." He said the politicians have "made Israel feel abandoned by the U.S."

Speaking at a press conference with Jens Stoltenberg, the secretary-general of NATO, Trudeau said today that sort of talk isn't welcome in Canada.

"I think Canadians and indeed people around the world know exactly what I think about those particular comments. That is not how we do things in Canada. A Canadian is a Canadian is a Canadian. The diversity of our country is actually one of our greatest strengths and a source of tremendous resilience and pride for Canadians and we will to continue to defend that," Trudeau said.

PM Justin Trudeau addresses tweets by President Trump telling four Congresswomen to go back to the countries they came from. 0:22

Trudeau did not say whether he'd personally define Trump's call for the four representatives to "go back and help fix the totally broken and crime infested places from which they came" as racist.

Outgoing British Prime Minister Theresa May also said the president's Twitter tirade was "completely unacceptable."

Ocasio-Cortez has denounced what she once called Israel's "occupation of Palestine" while advocating for cuts to U.S. foreign aid for the Middle Eastern country. Omar has been accused of using negative and harmful stereotypes of Jewish Americans. Tlaib, the first Palestinian-American congresswoman, has compared the Israel-Palestine situation to past racial segregation in the U.S.

'Socialist' congresswomen

U.S. House Speaker Nancy Pelosi, the highest ranking Democrat in Congress, said the president's comments suggested Trump was advocating white nationalism.

"When @realDonaldTrump tells four American Congresswomen to go back to their countries, he reaffirms his plan to 'Make America Great Again' has always been about making America white again," she said in a tweet.

In response, Trump said Pelosi's tweet was "very racist ... that's a very racist statement. I'm surprised she'd say that."

When <a href="https://twitter.com/realDonaldTrump?ref_src=twsrc%5Etfw">@realDonaldTrump</a> tells four American Congresswomen to go back to their countries, he reaffirms his plan to “Make America Great Again” has always been about making America white again.<br><br>Our diversity is our strength and our unity is our power. <a href="https://t.co/ODqqHneyES">https://t.co/ODqqHneyES</a> —@SpeakerPelosi

During a press conference at the White House Monday, Trump denied the tweets were racially motivated and said it was rather an attempt to denounce "socialist" congresswomen who frequently complain about the state of affairs in America.

Trump said that he thinks these congresswomen "hate our country" and announced he isn't afraid to "take them on."

"If you hate our country, if you're not happy here, you can leave and that's what I say all the time ... If you're not happy in the U.S., if you're complaining all the time, very simply, you can leave, you can leave right now," Trump said. "Come back if you want, don't come back, that's OK too but, if you're not happy, you can leave."