Apple is being sued by Taiwanese smartphone manufacturer HTC in the UK.
Bloomberg reports that no other details of the complaint - filed on 29 July - have been released, but notes that it comes two weeks after HTC lost a ruling against Apple at the US International Trade Commission. HTC was judged to have infringed on two Apple patents.
Industry-watchers said that the latest moves showed HTC's determination to keep the dispute running.
"By filing a lawsuit in Europe, HTC shows its determination to keep fighting. That determination is beyond doubt. But no matter in how many countries HTC may file lawsuits against Apple, it won't be able to change anything about Apple's objectives. Apple optimizes for product differentiation, not patent licensing revenues," said Florian Mueller, intellectual property activist, on the FOSS Patents blog.