YOKOSUKA, Kanagawa Pref. -- Prime Minister Keizo Obuchi, speaking at a National Defense Academy graduation ceremony Monday, reiterated his pledge to win quick Diet approval of bills to cover revised Japan-U.S. defense cooperation guidelines.

Before a large assembly of cadets, their families and students, Obuchi stressed the significance of Japan's military alliance with the United States, saying Japan need only strengthen existing bilateral ties.

"(Japan's) relationship with the U.S. is the most important bilateral relationship for our country," Obuchi said. "The security alliance with the U.S. is the core of our national security policy, and it is playing a significant role toward peace and stability in the Asia-Pacific region."

Also speaking at the ceremony, Defense Agency Director General Hosei Norota told the future Self-Defense Forces officers that Japan's biggest military concern at the moment is on the Korean Peninsula.

"In addition to the continuing military confrontation between South and North Korea, the launch of a ballistic missile by Pyongyang last year has cast a serious question over our national security as well as over the peace and stability of Northeast Asia," Norota said.

He said Japan has held a series of meaningful security talks with Seoul since Norota's visit to South Korea in January, adding that Tokyo and Seoul have agreed to further beef up the two countries' emergency communications framework in preparation for possible emergencies on the peninsula.