Speaking to reporters following the first day of meetings in Washington, D.C., Motegi said trade talks were progressing but he refrained from commenting on individual items.
"We agreed to speed up talks," Motegi told reporters after the meeting with U.S. Trade Representative Robert Lighthizer.
"There is no doubt that talks are moving along. We have not completely agreed at the moment, so we will deepen our talks."
U.S. President Donald Trump has repeatedly said he is unhappy with Japan's trade surplus with the United States, much of it from auto exports, and wants a bilateral deal to fix it.
Trump has pressured Tokyo to accelerate talks for a bilateral trade deal that would open up Japan's protected agriculture markets, such as beef and rice.
Asked about the prospect for an agreement, Motegi said he and Lighthizer didn't discuss the details of the timing.
"We share the understanding that we don't have much time," Motegi told reporters. They will resume talks Friday.
Bilateral trade talks could speed up as Japanese Prime Minister Shinzo Abe is expected to visit New York in September, where he is expected to meet Trump.