San Francisco, Dec 31 (DPA) Sony has taken the plunge into the escalating mobile phone patent wars. The Japanese electronics company has sued South Korean rival LG for patent infringement, claiming that LG's mobile phones violate seven Sony patents, according to court documents.

Sony filed the patent suit Wednesday with the US International Trade Commission (ITC) and with the US District Court in Los Angeles.

The legal action alleged that the LG phones violated Sony patents on band-width allocation, image capture, audio recording, network management and using photos as part of a caller ID system.

In filing the lawsuit, Sony joins a growing list of companies which have filed patent violation complaints over technology used in increasingly sophisticated smartphones. These include Apple, Microsoft, HTC, and Nokia.

Sony claimed that the patents allegedly infringed upon by LG had been licensed to other companies such as Nokia, Samsung and Sony Ericsson.

In the lawsuit, Sony asked the ITC to block imports to the US of LG phones that use the contested technology.

The legal action coincided with reports from Japan that Sony is to release a smartphone based on its PSP3 portable gaming console as it tries to make a late effort to thwart the threat posed by Apple's iPhone and phones powered by Google's Android operating system.