The legal battle between Nokia and Apple shows no signs of letting up anytime soon.
Apple on Tuesday sued Nokia in the U.K. claiming that one of the company's patents is invalid, according to Bloomberg. The patent in question describes a scrolling technology on touch-screen handsets and is one of the patents Nokia previously sued Apple for violating.
Nokia responded to the suit saying it is confident its patents are valid and it "will take whatever actions are needed to protect our rights."
Apple representatives were not immediately available for comment.
The legal tangle between the two companies has been going on since 2009 when Nokia first sued Apple for violating 10 of its patents. Two months later, Apple filed a countersuit listing 10 patents it believed Nokia was violating.
Bruce Sewell, Apple's general counsel, said at the time that "companies must compete with us by inventing their own technologies, not just by stealing ours."
The lawsuits and countersuits now span multiple countries including the U.S., U.K., Germany, and the Netherlands.