Samsung Electronics has filed patent lawsuits against Apple in South Korea, Japan and Germany, a week after the world's top technology company claimed Samsung's smartphones and tablets "slavishly" copied its products.
The South Korean firm said in a statement the suit involved infringements of up to five patents but did not elaborate on the technologies involved.
"Samsung is responding actively to the legal action taken against us in order to protect our intellectual property and to ensure our continued innovation and growth in the mobile communications business," the statement said.
Apple filed a lawsuit last Friday alleging Samsung violated patents and trademarks of its iPhone and iPad, as the popular gadgets are being threatened by the fast rise of rival devices based on Google's Android operating system.
Samsung is one of the fastest growing smartphone makers on the back of the Android boom and has emerged as Apple's strongest competitor in the tablet market, with models in three sizes.
Global technology companies are locked in a web of litigation as they try to defend their shares of the booming tablet and smartphone market.
The legal battle between Apple and Samsung could potentially jeopardise the earnings growth of the two technology giants, as Apple depends heavily on Samsung for components such as chips and LCD displays.
Strong sales of the iPhone and iPad translate into more revenue for Samsung. Apple was Samsung's second-biggest client after Japan's Sony Corp last year, bringing in around 6.2 trillion won of sales.
(Reporting by Miyoung Kim; Editing by Jonathan Hopfner).