The defense secretary of the United States will visit South Korea next week for talks with his local counterpart on key pending security issues, Seoul's defense ministry said Tuesday, with attention drawn to the possible deployment of an advanced U.S. missile-defense system here.

"For now, Secretary of Defense Ashton Carter is scheduled to come here on April 9 for a three-day stay," defense ministry spokesman Kim Min-seok said at a regular briefing without further elaboration.

A Seoul source, requesting anonymity, said, "During the visit, he plans to hold talks with South Korea's defense minister, Han Min-koo, and meet with President Park Geun-hye," adding, "A variety of issues of mutual concern is expected to be discussed, including how to deal with North Korea and ways to further boost the alliance."

Sources in Washington have said Carter is also expected to visit Japan in what will be his first trip to Northeast Asia since taking office last month. He visited U.S. troops in Afghanistan days after his inauguration.

The top U.S. defense official's planned visit comes amid speculation that Seoul and Washington could discuss the possible deployment of a Terminal High-Altitude Area Defense battery on South Korean soil.

The U.S. has expressed its willingness to deploy one here to better defend South Korea from the North's security threats and to guarantee the safety of around 28,000 U.S. troops stationed here and their families. Other countries in the region, including China, are against the move.

During his confirmation hearing in February, Carter pledged to significantly beef up missile defense, including deploying more ground-based missile interceptors in California and Alaska, saying North Korean missiles could pose a "direct threat" to the country.

Last week, U.S. Joint Chiefs of Staff Chairman Martin Dempsey said he had "productive conversations" with his South Korean counterpart, Adm. Choi Yun-hee, in Seoul on their progress in building an integrated air and missile-defense system, though officials here said THAAD was not on the agenda.

Meanwhile, U.S. Secretary of State John Kerry is widely expected to visit South Korea next month as part of his regional tour that will also likely take him to China and Japan.

"Nothing has been decided. Seoul and Washington are still in consultations (on the issue)," an official at Seoul's foreign ministry said. (Yonhap)