Bayer Schering Pharma AG said Tuesday that it filed an infringement suit against Teva Pharmaceutical Industries Ltd. (TEVA), which has launched a generic version of Bayer's YAZ birth control drug in the U.S.

"We've filed an infringement suit in the U.S. state of Delaware," a spokesman for Bayer Schering Pharma told Dow Jones Newswires.

"We believe [the generic drug] constitutes an act of infringement on intellectual property," the spokesman for Bayer Schering Pharma had said earlier, adding "We will defend ourselves."

In a press release, Teva said earlier Tuesday it has commercially launched Gianvi, a generic version of YAZ. The company said it has the right to launch an authorized generic version of YAZ supplied by Bayer in July 2011. Teva was not immediately available for further comment.

Bayer Schering Pharma is the pharmaceutical division of Germany's Bayer AG (BAYN.XE). The total sales of YAZ tablets in the U.S. were about $782 million in 2009, according to German research group IMS data.

-By Sarah Sloat, Dow Jones Newswires; +49 69 29725521; sarah.sloat@dowjones.com