Democratic U.S. Senate candidate Andrew Romanoff won endorsements Wednesday from a national grassroots progressive organization and a Colorado-based group devoted to strengthening the position of Latinos.

With just six days before ballots are due, the heated primary between Romanoff, a former speaker of the Colorado state House, and former Gov. John Hickenlooper is reaching a furious pitch, with dueling ads and fresh endorsements rolled out on a near-daily basis. The winner faces Republican U.S. Sen. Cory Gardner, considered among the most vulnerable Senate incumbents up for election this year.

A spokeswoman for Progressive Change Campaign Committee took a swing at Hickenlooper in a statement formally endorsing Romanoff on the heels of strong performances by progressive candidates in primaries in New York and Kentucky.

“Colorado is one of the most winnable Senate seats, and there’s no excuse for electing a corrupt, corporate Democrat who fights progress at a time when we need bold transformational leaders who get the urgency of this moment,” said Maria Langholz in a statement.

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“Romanoff is making the case for a Green New Deal and Medicare for All, while Hickenlooper consistently attacked (U.S. Sens. Elizabeth) Warren and (Bernie) Sanders from the right on these same issues in his failed run for president.”

Hickenlooper got attention during his While House bid last year for calling out the sweeping climate change proposal and single-payer health care plan as non-starters with voters. He also clashed with Warren and Sanders, who also ran in the presidential primary, at one point denouncing the Democrats for embracing elements of Sanders’ democratic socialist platform.

Warren on Saturday endorsed Hickenlooper in the Senate primary.

Hickenlooper nabs endorsements from former presidential primary rivals Elizabeth Warren, Cory Booker

Romanoff described the Green New Deal and Medicare for All as “pillars” of his campaign, along with comprehensive immigration reform and an equitable economy, in a statement welcoming PCCC’s endorsement.

“We are a nation in crisis and now is not a time for timidity,” he said. “We’re igniting something here in Colorado and have an opportunity to elect someone ready to combat climate change and income inequality who will fight for meaningful social justice reform. As Colorado’s senator, I know we’re going to meet this moment together and I am proud to have the PCCC by my side.”

The Colorado Latino Forum called Romanoff “the only progressive in this race” in its endorsement.

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“The Colorado Latino Forum supports Andrew Romanoff’s commitment to environmental justice, the Green New Deal, supporting public education, and public school teachers, the pursuit to protect Social Security and Medicare, legislation to protect victims of domestic violence/sexual assault, working toward pro-immigration legislation, DACA protections and much more,” the group said.

Ballots in Colorado’s primary are due to county clerks by 7 p.m. June 30.