Last Friday Apple won a round in its patent fight with Nokia as the United States International Trade Commission judge ruled that the U.S. company did not violate any of five Nokia patents.
Nokia said it does not agree with the ITC's initial determination and was waiting to see the full details of the ruling before deciding on the next steps in that case.
There is a significant degree of frustration shining through Nokia's announcement ... but more than anything else, Nokia is sending out a strong and unambiguous message that at the end of this epic battle Apple is going to have to send royalty checks to Finland, said Florian Mueller, independent specialist and blogger on patent battles.
Legal battles have become increasingly common in the cellphone industry since Apple and Google
Shares in Nokia were 0.9 percent lower by 1415 GMT, while Apple shares were 0.2 percent lower.
This not only highlights the importance and complexity of intellectual property issues in mobile, but underlines that there is unlikely to be any swift settlement, said Geoff Blaber, analyst at British consultancy CCS Insight.
On Tuesday Nokia filed a new case relating to seven patents in areas of multi-tasking operating systems, data synchronization, positioning, call quality and the use of Bluetooth accessories.
Our latest ITC filing means we now have 46 Nokia patents in suit against Apple, many filed more than 10 years before Apple made its first iPhone, Paul Melin, Nokia's vice president, intellectual property, said in a statement.
Legal disputes between the two technology groups are also being heard in courts in the United States, Britain, Germany and the Netherlands.
Apple has become an unstoppable force in two mobile segments that Nokia missed -- smartphones and content. These additional suits is one way for Nokia to try and distract Apple but market momentum is working against Nokia, said Steven Nathasingh, chief executive of U.S. research firm Vaxa Inc.
(Editing by David Holmes and David Cowell)