They also agreed that the two countries will try to reach a conclusion on the relocation of a U.S. Marine base in Okinawa Prefecture "as quickly as possible" through a new ministerial-level working group, Okada told reporters after meeting with Clinton in Singapore on the sidelines of a two-day Asia-Pacific Economic Cooperation ministerial meeting through Thursday.

They reaffirmed cooperation in addressing North Korea's nuclear ambitions, as Clinton briefed Okada about a U.S. plan to send Stephen Bosworth, special representative for North Korean policy, to Pyongyang in the near future to pave the way for a resumption of the stalled six-party denuclearization talks.

Okada said he and Clinton agreed to ensure success of a two-day visit to Tokyo by U.S. President Barack Obama from Friday, including talks Friday with Japanese Prime Minister Yukio Hatoyama.