The HTC One X and Evo 4G LTE are notable devices for many reasons, but today they become notorious: they're the first devices to face an import delay at US Customs for potentially infringing an Apple patent. We've learned today that the One X and Evo 4G LTE are indefinitely delayed at Customs as the agency investigates patent issues with Apple, and sources have further confirmed that some shipments are indeed being held back. The One X is also currently out of stock at AT&T's online store and at most AT&T retail stores we've called — and few had any information on when more units would arrive.

Apple won a wide-ranging exclusion order banning the importation of HTC Android devices at the International Trade Commission last December — the ITC found that Android's messaging app and browser infringed upon Apple patent #5,946,647, which covers automatically converting things like phone numbers and email addresses into actionable links that open a menu of options. The ban was delayed so HTC could engineer around Apple's patent claims, but it went into effect on April 19th — and although HTC claimed so-called "data tapping" was a "small UI experience" that would be completely removed from its US Android devices, Customs is now reviewing the One X and Evo 4G LTE.

Although the ITC order was handed down before the One X was even announced at Mobile World Congress, it's open-ended enough to block importation of any HTC Android device — the ITC broadly prohibited the importation of HTC "personal data and mobile communications devices" running Android that infringe the '647 patent. Customs and Border Protection is in charge of executing the order, and it's allowed to handle things pretty much any way it wants; there are really no formal rules governing how exclusion orders are interpreted or enforced. What's more, the final enforcement instructions delivered by Customs to its officers are totally classified — they're even excluded from Freedom of Information Act requests. At this point HTC is basically in limbo while it waits for Customs to issue a decision.

HTC can certainly try to stay the ban while it further appeals the case; the company's official statement is below. We've also reached out to Apple, AT&T, and Sprint, we'll update you as we learn more.

The US availability of the HTC One X and HTC EVO 4G LTE has been delayed due to a standard U.S. Customs review of shipments that is required after an ITC exclusion order. We believe we are in compliance with the ruling and HTC is working closely with Customs to secure approval. The HTC One X and HTC Evo 4G LTE have been received enthusiastically by customers and we appreciate their patience as we work to get these products into their hands as soon as possible.

This article originally appeared on as HTC One X and Evo 4G LTE indefinitely delayed at US Customs for investigation of Apple patent infringement .