"I did not run for Congress to be silent," she wrote. "No one person – no matter how corrupt, inept, or vicious – can threaten my unwavering love for America," she continued, without naming Trump directly. "Thank you for standing with me – against an administration that ran on banning Muslims from this country – to fight for the America we all deserve."

On Friday, the president tweeted a video that used footage of 9/11 with comments Omar made at the Council on American-Islamic Relations. The 43-second video captures Omar saying "some people did something,” in reference to terrorists who killed thousands when they crashed planes into the World Trade Center, the Pentagon and a field in Pennsylvania. The video, which features dramatic music and video of the chaos in downtown Manhattan, asks "Some people did something?”

But it does not show the entirety of Omar’s comments.

"For far too long we have lived with the discomfort of being a second-class citizen and, frankly, I’m tired of it, and every single Muslim in this country should be tired of it,” Omar said at CAIR in California last March. "CAIR was founded after 9/11 because they recognized that some people did something and that all of us were starting to lose access to our civil liberties.”

Omar went on to say that the 9/11 attacks changed how Muslims are viewed in America, and encouraged Muslims to not tolerate being treated as "second-class” citizens.

But conservatives viewed Omar’s comments as dismissive of 9/11.

"First Member of Congress to ever describe terrorists who killed thousands of Americans on 9/11 as "some people who did something. Unbelievable,” wrote Texas Republican Rep. Dan Crenshaw, an Afghanistan war veteran.

Democrats quickly came to Omar’s defense, and suggested the president’s tweet took Omar’s words out of context and could potentially endanger Omar. Last week, a man was arrested for threatening to kill Omar because she is Muslim.

Speaker of the House Nancy Pelosi tweeted that the president should not use images of 9/11 for political purposes.

"The memory of 9/11 is sacred ground, and any discussion of it must be done with reverence. The President shouldn’t use the painful images of 9/11 for a political attack," Pelosi wrote.

Fellow Democratic freshman Alexandria Ocasio-Cortez, of New York, called on Democrats to respond to Trump’s tweet and said that Omar's "life is in danger."

"Members of Congress have a duty to respond to the President’s explicit attack today.@IlhanMN’s life is in danger. For our colleagues to be silent is to be complicit in the outright, dangerous targeting of a member of Congress,” Ocasio-Cortez wrote.

Democratic presidential hopefuls also hit back at Trump’s tweet.

Sen. Amy Klobuchar, D-Minn., and South Bend, Indiana, Mayor Pete Buttigieg accused the president of inciting hate and violence.

"Someone has already been charged with a serious threat on Congresswoman Omar’s life," Klobuchar wrote. "The video the President chose to send out today will only incite more hate. You can disagree with her words—as I have done before—but this video is wrong. Enough.”

For his part, Buttigieg tweeted that "[t]he threats against the life of @IlhanMN make clear what is at stake if we fail to to do this, and to beat back hate in all all its forms.”

"After 9/11 we all said we were changed," he wrote in one of a series of tweets. "That we were stronger and more united. That’s what ‘never forget’ was about. Now, a president uses that dark day to incite his base against a member of Congress, as if for sport. As if we learned nothing that day about the workings of hate.”

Sen. Bernie Sanders, I-Vt., tweeted, "Ilhan Omar is a leader with strength and courage. She won't back down to Trump's racism and hate, and neither will we. The disgusting and dangerous attacks against her must end.”

It’s not the first time Omar’s comments have sparked controversy. Shortly after entering office, Omar accused Israel of having too much power in Washington because of its powerful financial lobbying and questioned the loyalty of some Jewish Americans.

"I want to talk about the political influence in this country that says it is OK for people to push for allegiance to a foreign country,” Omar said. Her comments were criticized as being anti-Semitic and accusing some Jewish people of having loyalty to both America and Israel. Omar apologized for her comment, but it sparked division among Democrats and even spurred an vote in the House aimed at denouncing anti-semitism, Islamophobia, and homophobia, among other things.