Apple Inc said it filed a countersuit against Nokia, claiming that the Finnish cellphone maker has pursued anti-competitive business practices and infringed on more than a dozen of its patents.

Apple, maker of the popular iPhone, was responding on Friday to a lawsuit that arch-rival Nokia filed in October. That suit accused Apple of infringing 10 Nokia patents for technologies such as wireless data, speech coding and security.

The countersuit heats up the fight between the two companies. While relative newcomer Apple trails Nokia in cellphone shipments, its iPhone has been gaining a lot of ground against the market leader in the smartphone segment.

In court documents, Apple denied infringing the Nokia patents and said that the patents asserted by Nokia were not essential for technology standards used in cellphones. It said the countersuit was filed in the same Delaware court where Nokia brought its case.

Apple also said that Nokia had engaged in anti-competitive behavior and did not live up to commitments to license its own technology at fair and reasonable terms.

The 13 patents that Apple cited in its countersuit involve various computing technologies including graphical interfaces, teleconferencing, power conservation and touch screen technologies -- features popularized by its iPhone.

In response, Nokia said that the countersuit does not change anything fundamental in the original case, but noted that it would take time to study the suit.

They have infringed our patents since the iPhone launch in 2007, a Nokia spokesman said.

While the battle may go on for some time, analysts see the companies eventually coming to a licensing agreement.

We can now look forward to a lengthy tit-for-tat exchange between Apple and Nokia as they grind out a deal, said Ben Wood, research director at CCS Insight.

Apple shares were down $1.92 or almost 1 percent at $194.51 on Nasdaq while Nokia's US shares were up 17 cents or 1.4 percent at $12.73 on New York Stock Exchange.

(Additional reporting by Tarmo Virki in Helsinki; Editing by Gerald E. McCormick, Phil Berlowitz) .

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