After failing to reach a deal by the much-touted 2013 deadline, the 12 economies negotiating the Trans-Pacific Partnership have pledged to keep striving for solutions to thorny issues, with the prospect of Japan-U.S. talks over farm products and cars as one of the keys for an early conclusion of the free trade pact.

A Japanese official said the TPP members could become even less motivated to make concessions after they missed the pledged deadline at a crucial four-day ministerial conference that ended Tuesday in Singapore, suggesting negotiations could now stretch on.

The United States was the most vocal about reaching a TPP agreement by the end of December as it seeks to rebuild its presence in Asia when China, a non-TPP member, is increasing its global influence, while trying to get an achievement before the midterm elections next year.