South Korea plans to wait and see how Japan's move to win the constitutional right to strengthen its military will affect Seoul's national interests, government sources said Friday.

South Korea's stance on the issue came after United States Secretary of State John Kerry and Secretary of Defense Chuck Hagel signed a landmark agreement with their Japanese counterparts on Thursday in Tokyo. The two countries pledged to further tighten their military cooperation and renew their bilateral defense cooperation guidelines for the first time since 1997.

In the meeting, the high-level officials from the two allies also officially confirmed Washington's endorsement and support of the Shinzo Abe administration's controversial plan to win the constitutional right to collective self-defense.

The Japanese post-war Constitution limits the role of its military to minor defense-only activities. The right-wing Abe government has repeatedly vowed to win a collective self-defense right, with the U.S. expressing support for the plan. It would help the U.S. employ Japanese soldiers and military weapons in overseas military operations.

Seoul has refrained so far from voicing clear support or opposition, despite strong criticism from some foreign countries that still remember cruel wartime atrocities by Japan in the early 20th century.

"We have not shifted from our previous stance that Japan's discussions on defense and security should be done under the basic ideology of its Peace Constitution and in a way that they allay neighbors' concerns resulting from history as well as in a way that they contribute to the regional peace," a government source said.

"It is difficult to say in one word what benefits Japan's collective self-defense right will give to us. We should accept what is beneficial and should resist what is not," the official said, adding that the government will wait and see how the Japanese plan takes shape.

Experts said Seoul is locked in a dilemma over Japan's military strengthening.

South Koreans, as key victims, still have bitter memory of Japan's harsh colonial rule and wartime atrocities during World War II. The public has largely opposed the move by Tokyo.

Seoul's trilateral military partnership with Tokyo and Washington does not allow outright opposition, especially amid rising security threats from North Korea's advancing nuclear programs, according to experts.

Japan's island of Okinawa, a military base for U.S. troops, is deemed a rear base for South Korea in the event of a war with the North. Japan's collective self-defense right will likely make it easy for the U.S. military to help South Korea utilize its military supplies there.

With Seoul sending only mixed signals, experts called on the government to clearly convey its concerns to Japan.

"Japan is seeking the collective self-defense right without clear self-reflection on its past invasion and aggression and that's problematic," said Hong Hyun-ik, an analyst at Sejong Institute. "Our government should voice this concern to Japan."

Seoul, however, needs a more careful approach, another government source said. "It has a lot of variables to consider, including China, the South Korea-U.S. alliance, as well as the relationship with Japan." (Yonhap News)