Dutch navigation device maker TomTom said on Friday it had launched a court case against Microsoft Corp a few weeks after the American software giant launched a patent lawsuit against it in the United States.

I can confirm that we are suing, a spokesman for the group said, declining to say where or on what grounds the case was lodged.

However a court filing showed TomTom filed a case against Microsoft in the state of Virginia on patent infringement grounds on March 16 (www.rfcexpress.com/lawsuit.asp?id=45136).

Microsoft launched its case after both companies failed to reach a patent-licensing agreement following more than a year of talks.

Although it looks as though the legal battle is heating up it is likely that the end result will have no or little impact on the business of TomTom, SNS analyst Martijn den Drijver said in a research note.

It is our opinion that the most likely outcome is that both companies, in the end, will agree to use each others patents in exchange for the lawsuits to be dropped.

TomTom shares were down 0.6 percent at 3.45 euros at 0858 GMT while the Dow Jones European index for Technological stocks was down 3.6 percent.

(Writing by Julien Ponthus; Editing by David Holmes and David Cowell)