VANCOUVER -- Lululemon Athletica Canada Inc. is suing exercise equipment company Peloton Interactive Inc. over allegations of patent infringement.

The Vancouver-based athletic apparel retailer claims in court documents that Peloton is selling “knock-off” Lululemon bras and leggings, infringing on multiple design patents.

The lawsuit filed on Monday in a U.S. court comes after Peloton ended a co-branding agreement with Lululemon earlier this year and launched its own private label clothing brand, Peloton Apparel, in September.

Lululemon alleges Peloton is selling “copy-cat products” that imitate several of the retailer's best-selling designs, including a pair of workout pants and a popular strappy sports bra.

The company says in court documents it initially sent Peloton a cease-and-desist letter, laying out its concerns with the exercise equipment maker's “blatant misappropriation.”

Lululemon says Peloton requested an extension to respond to those allegations, but then used the delay to “secretly prepare its own complaint and pre-empt the lawsuit that Lululemon had so clearly threatened.”

Last week, Peloton sued Lululemon, asking a U.S. Federal Court to declare that it has not infringed on Lululemon patents.