Kris Jenner: Jewelry War Heats Up ... We Ain't Too Proud to Sue

Kris Jenner is way too proud about her #ProudMama ... according to the jeweler who's one step closer to launching a full-scale legal war over the hashtag.

TMZ broke the story ... Jenny Present, who owns a jewelry company and the trademarked phrase "Proud Mama," issued a warning to Jenner when the momager attempted to get her own trademark.

Present says Kris hasn't backed down, so she's just fired off a cease and desist letter to the momager's company. Tensions are definitely rising since Kris recently announced she's doing her own jewelry collection.

Present's letter demands Jenner stop using #ProudMama on all promotional platforms.