U.S. Sen. Kirsten Gillibrand on Sunday endorsed several challengers to the lawmakers who formerly comprised the Independent Democratic Conference — the most high-profile establishment official in the state to back their primary candidacies.

Gillibrand endorsed Alessandra Biaggi, who faces Sen. Jeff Klein, Zellnor Myrie over Sen. Jesse Hamilton, Jessica Ramos over Sen. Jose Peralta and Robert Jackson, who is challenging Sen. Marisol Alcantara.

In at least one instance, Gillibrand is also providing some fundraising heft for Biaggi, releasing an email with her name and image on her behalf.

“Alessandra Biaggi will bring new energy to the State Senate and add an important voice in Albany to so many battles that are important to me—from the fight to improve access to health care and the quality of our public schools, to environmental protection and affordable housing, to the urgent need to safeguard our right to choose,” Gillibrand wrote in the fundraising email.

The Jackson campaign sought to use the endorsement as an organizing tool for supporters.

“Robert Jackson is a tireless fighter for progressive values who we can trust to stand up for what’s right,” Gillibrand said.

“A public school hero for his landmark lawsuit and walk to Albany to demand full funding for NYC’s public school students, Robert has fought to protect tenants, make healthcare more affordable and to promote fairness, justice and equality. He will help bring the progressive change we need in the State Senate and I look forward to working with him.”

The agreement that led to the dissolution of the IDC in April and its members rejoining the Democratic conference required that Gov. Andrew Cuomo and Senate Democrats do not provide support to the primary challengers.

But multiple elected Democratic officials, including members of the state’s congressional delegation and Mayor Bill de Blasio, aren’t bound to that agreement and have provided endorsements to the challengers.