U.S. House challenger Crisanta Duran earned an endorsement Friday from Ken Salazar, one of the state’s most prominent Democrats.

In a fundraising email distributed by Duran’s campaign at 5 p.m. Friday, Salazar said he has known Duran for many years and called her “a force to be reckoned with.” Salazar, a former U.S. senator and Interior secretary, said she will cut through dysfunction in Washington and “build a stronger, more confident Democratic majority.”

“Crisanta will be the fighter we need in Congress to move our nation forward,” Salazar said.

Duran, former Colorado House speaker, announced last month that she is challenging veteran Rep. Diana DeGette, a fellow Denver Democrat, in next year’s 1st Congressional District primary.

Salazar served in Congress with DeGette from 2005 to 2009. His endorsement of her opponent is the strongest indication to date that Duran could raise a serious primary challenge.

A DeGette spokesperson, Lisa Cohen, said the campaign wouldn’t comment on an individual endorsement.

“The people of Colorado are tired of these non-stop election cycles,” Cohen said in a written statement. “They want somebody who is going to fight for them in Congress. That’s why, right now, Rep. DeGette is focused on doing her job and ensuring the full Mueller report is made available to the public, not just a summary.”