As President Donald Trump continued to assail Rep. Ilhan Omar Monday, hundreds of progressive leaders affirmed their support for the freshman congresswoman and called on other members of Congress to denounce the "constant racist and bigoted attacks" she faces.

Initiating signers include American Federation of Teachers president Randi Weingarten; Color of Change executive director Rashad Robinson; and Democracy for America chief executive Yvette Simpson. Over two hundred other progressive leaders have signed on as well.

In their new letter, the progressives describe Omar as "a visionary and inspiring leader" who's facing attacks that are "beyond the pale."

The reason for those attacks is clear, the letter states.

It's because of her strident leadership of progressive values, as well as her identity as the first Black Muslim woman in Congress, that she is a target of constant racist and bigoted attacks from Donald Trump, right-wing media and extremists, Republican leaders, and even, at times, Democratic colleagues.

Moreover, the attacks serve a purpose—"to divide and distract us, while Trump and the GOP undermine our democracy and enrich themselves and their friends."

"We call on all members of Congress to speak out against these attacks and stand with Rep. Omar and against the racist and bigoted rhetoric, policies, and violence," the letter concludes.

Public Citizen, whose president Robert Weissman is among the signatories, tweeted: "The progressive community has got your back, @IlhanMN."

The letter comes a day after Omar said she'd experienced an uptick in death threats. Some of those threats, Omar said, were issued as a reply to an edited smear video Trump tweeted on Friday.

"Violent crimes and other acts of hate by right-wing extremists and white nationalists are on the rise in this country and around the world," Omar said. "We can no longer ignore that they are being encouraged by the occupant of the highest office in the land."