"Korea comes under that," she said during a discussion at the Center for Strategic and International Studies.

She added that once the administration completes its review of US burden-sharing policy worldwide, it hopes to "soon" begin negotiations to renew the cost-sharing deal, known as the Special Measures Agreement, with South Korea.

"And we will be asking for more of Korea's contribution to the stationing of forces in Korea," Yamamoto said, without providing details.

The allies have shared the burden of stationing some 28,500 American troops in South Korea, a legacy of the 1950-53 Korean War that has continued both to deter North Korean aggression and defend US strategic interests against China's economic and military rise.

In March, Seoul and Washington signed a one-year contract calling for an 8.2 percent increase in South Korea's share to 1.04 trillion won ($915 million).

The deal was reached after multiple rounds of talks during which the US reportedly demanded a hike of Seoul's share to some 1.2 billion won. Washington also sought a one-year contract, while Seoul wanted it to last three to five years.

Negotiations for next year's agreement are expected to begin in the coming months. (Yonhap)