The Obama administration on Wednesday notified Congress it will start free-trade talks with Japan, after more than a year of consultations with Tokyo over joining negotiations on a regional free-trade pact.
"The participation of Japan, a major US trading partner as well as close ally, further increases the economic significance of a Trans-Pacific Partnership Agreement," acting US Trade Representative Demetrios Marantis said in a letter to congressional leaders.
The 90-day notification was expected after a deal was reached on 12 April on the terms of Japan's entry into the TPP talks, which are now in their fourth year.
The United States and the 10 other countries already involved in the TPP talks on Saturday formally approved Japan's entry into the negotiations at a meeting of regional trade ministers in Indonesia.
Mr Marantis sought to reassure Congress that Japan's participation would not slow the TPP negotiations, which are scheduled for conclusion by the end of the year, and that Japan would not refuse to negotiate in sensitive agricultural and manufacturing sectors of interest to US exporters.
"Japan has confirmed it will participate positively and constructively in the negotiations. Japan also confirmed that it will subject all goods to negotiations - both agricultural and manufactured goods - and will join with the other TPP countries to achieve a high-standard and comprehensive agreement this year," he said.
Countries around the world are moving increasingly toward regional free-trade agreements in the absence of any progress toward a comprehensive world trade deal.