Japan and the United States made only "very limited" progress in two days of working-level talks over Tokyo's proposed exceptions to tariff abolition for key farm products under the Trans-Pacific Partnership, a Japanese official said Wednesday.

"We were not able to make as much progress as we had expected," Hiroshi Oe, deputy chief negotiator for the free trade talks, told reporters after wrapping up the working-level meeting with acting Deputy U.S. Trade Representative Wendy Cutler in Tokyo.

The failure between the two largest economies in the TPP to bridge their differences clouds the prospect of striking a two-way agreement by the end of this month, seen as vital before all 12 TPP negotiating members reach an agreement.

Given that Washington envisions finalizing a TPP agreement by the end of this year, Akira Amari, minister in charge of the TPP, said earlier that it was desirable for Tokyo and Washington to reach a broad deal at the ministerial level this month.

Oe, however, said it is still premature for the bilateral talks to be brought to ministers, saying there are "considerable gaps" between the two.

The main focus has been how drastically Japan should cut tariffs on beef and pork — one of Tokyo's five sensitive farm product categories — and safeguard measures it seeks to introduce should imports of the products surge under the TPP.

Oe also added that his side felt a need to wrap up tariff talks with the U.S. "within a month or two" to accelerate the 12-nation negotiations.