Sen. Cory Booker (D-N.J.) slammed President Donald Trump’s attacks against Rep. Ilhan Omar(D-Minn.) as “toxic” and “reprehensible” during a forum on Wednesday for presidential candidates in Houston.

“The criticisms of Congresswoman Omar, what Trump has been saying about her, is reprehensible,” Booker said at the forum organized by She The People, a national network of women of color in politics. “It is trafficking in Islamophobia, and should be condemned by everyone.”

Omar, a black woman and one of the nation’s first Muslim congresswomen, has come under repeated attack from the president, pundits and lawmakers since she made statements questioning the U.S.’s relationship with Israel.

In mid-April, Trump tweeted “WE WILL NEVER FORGET” while sharing a misleading video that spliced together comments Omar made last month with footage of the Sept. 11 terrorist attacks.

Omar said death threats against her had increased after the president’s tweet, with her office noting that many directly referenced the video Trump had shared.

Despite this, Trump has continued his assault on Omar, tweeting that people should look at her “anti-Semitic, anti-Israel and ungrateful U.S. HATE statements” and her “control” of House Speaker Nancy Pelosi (D-Calif.).

“The kind of language this president uses, especially about black women in power, is toxic,” Booker said Wednesday. Trump has publicly attacked other high-profile black women in the past, such as Rep. Maxine Waters (D-Calif.).

Booker said Trump’s language “fuels the kind of hate” behind terror attacks in the U.S., which he noted were largely perpetrated by members of far-right groups, including white supremacists.

“It’s not enough to say, ‘I’m not a racist,’” Booker added. “We must all be anti-racist.”