South Korea's new government will continue prioritizing its relations with the United States over China, Seoul's foreign minister-nominee said Wednesday, stressing the importance of the alliance between the two countries.

Yun Byung-se made the remarks in a report submitted to independent lawmaker Park Joo-sun ahead of his parliamentary confirmation hearing.

"The U.S. is our country's first-priority diplomatic partner and China comes next," the nominee said in the report. "In case of Japan and Russia, the two nations are also our important partners for peace and prosperity on the Korean Peninsula and in Northeast Asia."

South Korea has been a staunch ally of the U.S. but a rising China is putting Seoul in a strategic and diplomatic dilemma between Washington and Beijing, the world's two superpowers.

Although China is South Korea's biggest trading partner, bilateral relations have been often testy when it comes to issues related to North Korea. China is the North's key ally, economic benefactor and diplomatic supporter.

With 32 years of experience in diplomacy, Yun is known for being one of the key architects of President Park Geun-hye's "trustpolitik" doctrine that calls for engagement with North Korea while standing firm against any provocations from the North.

North Korea's third underground nuclear test on Feb. 12, however, is set to thrust the nominee into a daunting security challenge.

Before joining Park's camp, Yun served as senior coordinator at the National Security Council and senior presidential secretary for foreign and security affairs until early 2008.

One of the major possible sticking points between South Korea and the U.S. in the coming months is Seoul's push to expand its non-military nuclear program, which Washington considers a nonproliferation issue.

Under a nuclear energy cooperation agreement signed in 1974, South Korea is banned from reprocessing spent fuel and enriching uranium. The pact expires in 2014.

South Korea wants the U.S. to allow it to use a new technology to reprocess spent atomic fuel because it has to deal with more than 10,000 tons of nuclear waste at storage facilities that are expected to reach capacity in 2016.

Asked about the issue, Yun replied, "Our target is to lay a ground work to expand the use of our peaceful nuclear energy." (Yonhap News)