Samsung Electronics Co said on Thursday it had filed a complaint with the U.S. International Trade Commission against Taiwan's AU Optronics Corp and some of its customers for importing and selling flat-screen devices that it says infringe a number of its patents.

Samsung, which vies for the top flat-screen position with local rival LG Display, said in a statement that it is seeking an order prohibiting the import and sale of the infringing LCD devices such as televisions, computer monitors and notebooks.

The South Korean firm said it had also filed two similar suits in U.S. District Court of Delaware and the District Court for the Northern District of California.

To protect its investment and customers, Samsung has -- and will continue -- to take action against any unauthorized use of its patented technology, it said in a statement.

AU Optronics was not immediately available for comment.

Samsung, Asia's most valuable technology company with around $137 billion in market value, is in a separate legal battle with Apple over mobile patent infringements.

Samsung counter-sued Apple in April after the Cupertino, California-based firm alleged that Samsung's smartphones and tablets slavishly copied its products.

By 0045 GMT (8:45 p.m. EDT), shares in Samsung fell 2.5 percent, lagging a 1.8 percent drop in the wider market.

(Reporting by Miyoung Kim; Editing by Ken Wills and David Chance)

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