– U.S. Rep. Ilhan Omar tweeted on Wednesday night that Republican Sen. Lindsey Graham is “compromised,” but offered no evidence for that assertion.

“They got to him, he is compromised!” the Minnesota Democrat wrote on Twitter, as she retweeted a CNN clip from 2015 in which Graham was heavily critical of President Donald Trump. He has since emerged as a Trump ally on Capitol Hill.

Omar was not immediately available for comment. A spokeswoman for Graham did not immediately return a phone message.

In an interview on CNN Thursday morning, Omar called her tweet “just an opinion” but did not otherwise back down from it. “My tweet was just an opinion based on what I believe to be visible to me, and I’m pretty sure there are lots of Americans who agree on this,” Omar said on CNN.

“Alleging that a sitting U.S. senator is being blackmailed or coerced is extremely troubling — especially when the allegations come with no backup and no evidence whatsoever,” said Jennifer Carnahan, chairwoman of the Minnesota Republican Party. “Rep. Omar is now in a position of power and should realize her words and tweets have consequences.” Omar “should use her platform responsibly, not to rile up her followers with nothing to back up her opinion,” Carnahan added.

Graham has been an ally of Trump; he met with him at the White House last week and has been a frequent defender in the press.

Graham has publicly supported Trump’s demand for a Mexico border wall in exchange for money to reopen the government, though this week he did urge Trump to temporarily reopen the government to be followed by negotiations over border security and immigration.

That was a shift from earlier, when Trump and Graham competed for the Republican presidential nomination leading up to 2016.

Graham was a frequent target of ridicule by Trump, and in the 2015 CNN interview, he responded with scorn.

“He’s a race-baiting, xenophobic religious bigot,” Graham said of Trump. “He doesn’t represent my party, he doesn’t represent the values that the men and women wearing the uniform are fighting for.”

Asked on CNN what evidence she could offer, Omar said: “The evidence really is present to us, it’s being presented to us in the way he’s behaving.”

She suggested it could be related to campaign funding, polling in his district, “or something to do with some sort of leadership in the Senate.”

A number of critics on Twitter suggested that Omar said or implied that the compromising information was of a sexual nature.

But Omar never said or implied that in her tweet or the CNN interview, which she pointed out in a subsequent tweet.

As the first Somali-American elected to Congress, Omar — who took office two weeks ago — has emerged as a national figure.

On Wednesday, her office announced that she has been appointed to the House Foreign Affairs Committee.

That panel oversees U.S. foreign assistance, foreign policy, treaties, peacekeeping and war powers.

Omar earlier in the week also landed a spot on the Education and Labor Committee, which oversees federal education programs from preschool to higher education.