Apple has begun legal proceedings against Nokia in the UK, accusing the mobile giant of infringing nine patents related to smartphone technology.
It is an extension of a lawsuit filed in the US in December 2009.
The long-running row began in October 2009 when Nokia filed a lawsuit against Apple claiming the iPhone and the iPad infringed 10 of its patents.
Nokia said it was "unsurprised" by the latest development.
"It changes nothing in the fundamentals of the matter, which are rooted in Apple's refusal to respect Nokia's intellectual property and attempt to free ride on the back of Nokia's innovation," Nokia said in a statement.
The patents Nokia accuses Apple of copying involve wireless data, speech coding, security and encryption.
At the time it launched its lawsuit it said it had agreements with around 40 firms allowing them to use the technology but that Apple had not signed up.
It is unclear what the exact nature of Apple's disputed patents is and the firm was not immediately commenting on the development.
In its US lawsuit it claims Nokia is infringing 13 Apple patents.
"Other companies must compete with us by inventing their own technologies, not just by stealing ours," Bruce Sewell, Apple's general counsel, said at the time.
Patrick Gearon, head of intellectual property at law firm Charles Russell, said the new wave of lawsuits could indicate a hardening line from Apple.
"These patents refer to smartphone processes which are extraordinarily valuable now. Apple could be ramping things up to force some kind of resolution," he said.