Apple could be banned from selling a range its products in Germany, including the iPhone 4S and the iPad 2, after Motorola won an injunction.
The case relates to wireless technology patents owned by Motorola and the decision to grant an injunction is a huge setback for Apple, who until now have had the upper hand in several ongoing legal disputes with technology rivals.
Apple confirmed it would appeal the ruling and told its customers in Germany that it was confident its products would remain on sale.
"We're going to appeal the court's ruling right away. Holiday shoppers in Germany should have no problem finding the iPad or iPhone they want," it said.
Motorola's general counsel Scott Offer welcomed the ruling as proof Motorola was right to take action against Apple in the courts.
"Today's decision validates Motorola's efforts to enforce its patents against Apple's infringement," he said.
"We have been negotiating with Apple and offering them reasonable licensing terms and conditions since 2007, and will continue our efforts to resolve our global patent dispute as soon as practicable."
Patent analyst Florian Mueller told V3 that Apple can no longer sell products that fall foul of the relevant patent unless it modifies the devices in question, which could prove unworkable.
"Apple is banned from selling all devices that infringe the patent-in-suit. If they dropped the patented functionality, they'd be fine, but it's unclear whether that's a viable option," he said.
He added that Apple would definitely appeal the ruling to try to hold up the injunction for the duration of the appeals proceedings.
If Apple fails to get the injunction suspended, Motorola will be able to enforce the ban on the products being sold in the country, but at the risk of severe financial loss further down the line due to the inclusion of a bond of €100m in the ruling, Mueller said.
"This is the amount Motorola might have to pay Apple if the injunction is later overturned by an appellate [appeals] court. If you enforce an improperly-granted injunction while it's being appealed, you're liable later if you lose," Mueller told V3.
The original bond request by Apple was a whopping €2bn but the judge lowered this to €100m.
The decision is a huge twist in the ongoing legal battles taking place between major smartphone and tablet vendors, which have seen Apple and Samsung in particular taking each other on in courts across the world.
Do you agree
Latest stories from Mobile Software