Samsung was repeatedly warned that its smartphones and tablets were too similar to Apple's counterparts and even discussed that issue internally, the iPhone maker claims in an unredacted court filing.

The brief, which was revealed by All Things D, emerges as the companies move closer to their high-stakes patent trial in the U.S., which is due to begin on Monday.

"Samsung's documents show the similarity of Samsung's products is no accident or, as Samsung would have it, a 'natural evolution,'" Apple argued in its brief. "Rather, it results from Samsung's deliberate plan to free-ride on the iPhone's and iPad's extraordinary success by copying their iconic designs and intuitive user interface. Apple will rely on Samsung's own documents, which tell an unambiguous story."

The documents highlight instances in which third parties, including Google, and Samsung's own employees warned the Korean electronics giant that its product designs bore a striking resemblance to Apple's, the Cupertino, Calif., company's brief said.

In one case, Google told Samsung in 2010 that its "P1" and "P2" tablets, which eventually became the Galaxy Tab and Galaxy Tab 10.1, were "too similar" to the iPad and requested "distinguishable design vis-a-vis the iPad for the P3." Samsung's own product design team remarked last year that it was "regrettable" that the Galaxy S "looks similar" to the iPhone.

CNET has contacted Samsung for comment and will update this report when we learn more.

Apple initiated the action with a 2011 lawsuit in California accusing Samsung of copying "the look and feel" of its iPad tablet and iPhone smartphone, and Samsung quickly responded with a countersuit against Apple.