SEOUL (Reuters) - South Korea's Samsung Electronics , the world's top maker of large-size liquid crystal display panels, said on Thursday it was countersuing Japan's Sharp Corp for patent infringement.

"We are countersuing Sharp in Delaware in the United States and in Tokyo," Samsung spokesman James Chung said.

"We have also requested the U.S. International Trade Commission to launch an investigation in this case," Chung said.

Sharp, the world's third-largest LCD TV maker behind Samsung and Sony Corp, sued Samsung earlier this month in the Seoul Central District Court for patent infringement. It also filed suit against Samsung in the United States in August.

"We plan to take appropriate legal countermeasures after studying the details of the legal claim," Sharp said in a statement.

Samsung's actions are the latest episode in a series of legal tussles among Asian technology companies as they increasingly focus on intellectual property to survive fierce competition.

Shares in Samsung fell 1 percent to end at 570,000 won, below the broader market's 0.1 percent rise. Shares in Sharp rose 0.5 percent, beating the Nikkei's 0.6 percent drop.

(Reporting by Marie-France Han; Additional reporting by Nathan Layne in Tokyo; Editing by Sei Chong)
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