North Korea is getting close to fielding an advanced short-range missile that has been tested successfully and will pose a new threat to South Korea, a departing Pentagon official said Friday.

Richard Lawless, at a final news conference after serving nearly five years as the Pentagon's top Asia policy official, said the new missile is more mobile and more accurate than the Scud missiles that already are targeting South Korea. Another concern is that the new missiles could be sold globally, Lawless said.

"As this system, this particular system, approaches operational status and is deployed in large numbers, you have for the first time in the North Korean inventory" a highly accurate missile "whose only purpose, given its range, is to strike the Republic of Korea," he said, using South Korea's official name.

Last week, North Korea test-fired three short-range missiles that U.S. officials said were the new, advanced version. Lawless said they have a range of 120 to 140 kilometers, or about 75 to 85 miles.

Lawless said little about the specifics of the testing, which he described as "basically successful."

The missiles are designed to carry non-nuclear warheads, although Gen. B.B. Bell, the top U.S. commander in South Korea, said on Monday that North Korea's continued development of ballistic missiles is a concern because of the possibility of them being coupled with the North's "demonstrated nuclear ability."

Lawless said U.S. officials are discussing the issue of the new short-range missiles with the Seoul government.

"We have a problem with this new system because it's much more accurate and it's much more survivable" than Scud missiles, Lawless said.