South Korean Foreign Minister Yu Myung-hwan speaks during a forum at the Press Center in Seoul, South Korea, on Monday. (Yonhap, Kim Hyun-tae/Associated Press)

South Korea's foreign minister called North Korea's uranium enrichment program "worrisome" and pressed the Communist nation Monday to take real steps toward nuclear disarmament.

In Seoul, Yu Myung-hwan said he believes the issue could be separately discussed at the United Nations. He did not elaborate.

Just last week, North Korea launched five short-range ballistic missiles into its eastern waters, and the country appears to be preparing to fire more. North Korea has announced a no-sail zone in areas off the country's east and west coasts for Oct. 10 to 20 — an apparent signal it would carry out more missile tests.

Last month, North Korea told the UN Security Council that it was in the final stages of enriching uranium, a process that would give the regime a second way to make atomic bombs in addition to its plutonium-based program.

Although it could not be verified independently, the claim has raised concerns that the North may add uranium-based weapons to enlarge its stockpile of nuclear bombs made from plutonium.

Analysts said at the time that the announcement was aimed at getting the U.S. to accept its demand for direct talks. North Korea has been reaching out to Seoul and Washington in recent months after months of raising tensions over its nuclear and missile programs, though it conducted short-range missile tests and warned of a naval clash with the South last week.

Yu was skeptical about North Korea's conciliatory gestures. He said North Korea must first take "substantial" disarmament measures and promptly return to stalled six-party disarmament talks involving the two Koreas, the U.S., China, Russia and Japan.

Yu said South Korea remains open to dialogue with the North but will continue to enforce sanctions on the country for its May nuclear test to get the North to return to the talks.