NEW YORK (Kyodo) Nissan North America Inc. said Thursday it has filed a damages suit against Audi AG, claiming the German carmaker poached the registered letter Q for its new sport utility vehicles.

The U.S. unit of Nissan Motor Co. has used Q as the first letter to identify some of its Infinity luxury vehicles since 1989, including the Q45. It says Q symbolizes quality and has registered the names with the U.S. Patent and Trademark Office.

Nissan also claims Audi's use of the Q5 and Q7 trademarks for the new SUVs might confuse consumers, and has asked a U.S. district court in Michigan to bar Audi from using any names that could infringe on Nissan's Q marks.

Audi, a subsidiary of Volkswagen AG, has usually used the letter A for most of its vehicles, including the A6 and A8 sedans. But it plans to market the Q7 SUV in 2006 and the Q5 later.