The former head of Toyota acknowledged Wednesday the successful carmaker was worried about a possible political backlash in the United States to his company's booming success there in stark contrast to struggling U.S. rivals.

"We are certainly concerned," Hiroshi Okuda, who is now a senior adviser to the automaker, told the audience at the American Chamber of Commerce in Japan, where he was given the ACCJ's 2006 Person of the Year award.

In recent months, U.S. lawmakers from manufacturing states have charged that the Japanese government has kept the yen artificially low, giving Japanese automakers an advantage, and that nearly half of the vehicles Toyota sells in the U.S. are imported.