The United States is frustrated with Japan's ban on U.S. beef imports but believes Tokyo is moving toward reopening its market despite consumer fears over mad cow disease, a U.S. agriculture official said Tuesday.

Chuck Lambert, U.S. deputy undersecretary of agriculture, said in an interview in Tokyo that the technical conditions for a resumption of beef imports to Japan have been met, and Washington is urging Tokyo to move faster.

"We are seeing signs of progress in the right direction," said Lambert, who was in Tokyo this week with a U.S. delegation to make their case on the beef issue. "We still believe that progress is painfully slow."