A Native American tribe and a small computer company have reportedly sued Amazon and Microsoft, claiming that they’re infringing on patents relating to supercomputer technology.

The lawsuits are the latest twists in a relatively new strategy under which companies assign patents to tribes that can in turn assert sovereign immunity to short-circuit review procedures.

Reuters and CNBC reported that the suits were filed today in federal district court in Virginia by the Saint Regis Mohawk Tribe and SRC Labs. SRC, a company founded in 1996 by the late supercomputer pioneer Seymour R. Cray, assigned the patents in question to the tribe in August.

Efforts to obtain comment from Amazon and Microsoft were not immediately successful, but if we hear anything back, we’ll update this story.

In a typical case of this sort, the companies would turn to what’s known as an “inter partes review” at the Patent Trial and Appeal Board to question the validity of patents on an expedited basis.

However, under current law, sovereign tribes are immune from challenge at the appeal board level. To take advantage of that provision, companies with potentially challengeable patents have started transferring those patents to tribes. The arrangement typically involves paying the tribes, with additional royalties if the patents are successfully defended.

The best-known case involves Allergan, which struck a $13.75 million deal with the Saint Regis Mohawk Tribe for the transfer of patents on its Restasis eye medication.

That deal was aimed at blocking the sale of generic drugs that use the same active ingredients as Restasis. Allergan’s strategy suffered a reversal this week, however, when the patents were thrown out by a federal judge in Texas. Allergan says it will appeal the ruling, but the controversy has led some in Congress to call for removing the sovereign immunity provision.

Yet another case involves Apple, which is being sued for patent infringement involving technologies used in its iPad 4 tablet. The plaintiff is MEC Resources, which is wholly owned by the Mandan, Hidatsa and Arikara Nation, based on the Fort Berthold Indian Reservation in North Dakota.

MEC Resources took control of the patents as part of a deal with Prowire, a Texas-based company that had previously sued Apple.