Japan and the United States still need to bridge gaps on controversial issues in the ongoing Trans-Pacific Partnership free trade talks, a Japanese senior vice minister said after meeting with the U.S. trade representative on Sunday.

On the sidelines of the 12-country TPP meeting being held in Singapore, Yasutoshi Nishimura and U.S. Trade Representative Michael Froman likely discussed issues including how to deal with Japanese tariffs on key farm products that Tokyo is seeking to protect.

Japan is facing tough negotiations in tariff-cutting talks, one of the most contentious fields, as the United States and the other TPP countries are putting strong pressure on Tokyo to open up its agricultural sector.