U.S. Trade Representative Ron Kirk says that trade imbalances between the U.S. and South Korea in the auto industry are a key point of contention in discussions about the ratification of a bilateral free trade deal.

Kirk made the remark Wednesday during a roundtable discussion with reporters, saying that he is discussing the issue with the U.S. Congress and American automakers.

Kirk also said that he will continue to pressure South Korea and Japan to import U.S. beef regardless of cattle age, noting the World Organization for Animal Health’s classification of the U.S. as a controlled risk country for mad cow disease.

But Kirk denied news reports that he would soon hold working-level talks to renegotiate the free trade agreement with South Korean Trade Minister Kim Jong-hoon, saying that no such schedule has been set.