SAN DIEGO (AP) — Negotiators from the United States and eight other Pacific Rim countries opened a round of talks Monday aimed at producing one of the most ambitious trade deals in decades amid criticism that the deliberations are shrouded in secrecy.

The United States has been negotiating the Trans-Pacific Partnership Free Trade Agreement for about three years. The talks include Australia, Brunei, Chile, Malaysia, New Zealand, Peru, Singapore and Vietnam. Mexico and Canada are expected to join, and Japan has expressed interest.