The 12 countries that signed the Trans-Pacific Partnership free trade pact earlier this year agreed Monday that they will not renegotiate the deal, Japan's TPP minister Nobuteru Ishihara said.

The minister also told reporters the 12 nations confirmed they will move ahead with domestic processes quickly to adopt the U.S.-led trade pact.

Ishihara's remarks came after he joined ambassadors and other representatives from 11 countries for a TPP meeting at the official residence of U.S. Ambassador to Japan Caroline Kennedy in Tokyo.

The gathering was held amid growing speculation the deal may not take effect despite its signing in February, as the main candidates in the U.S. presidential election — Republican Donald Trump and Democrat Hillary Clinton — have both criticized the pact.

Kennedy said U.S. President Barack Obama has pledged to make efforts to get Congress to endorse the TPP by the end of the year, the Cabinet Office in Japan said.

Ishihara told reporters later that Prime Minister Shinzo Abe's team will work to ratify TPP at the extra Diet session expected to start on Sept. 26. The TPP would let Abe claim progress in structural reforms — the missing third arrow of his sputtering Abenomics growth strategy.