North Korea has extended the range of its No-Dong missile in a move that could benefit Pyongyang's clients in the Middle East, Iran in particular.

The No-Dong intermediate-range missiles was said to have been extended over the last year in a North Korean research and development effort, Asian intelligence sources said. They said North Korea appeared to have employed advanced technology to reduce the weight of the warheads to extend the range of the No-Dong.

The Japanese business daily Nikkei Shimbun said North Korea extended the range of the No-Dong by reducing the weight of warheads and improving technology. The daily, in a report on June 2, did not elaborate.

Iran's Shihab-3 began as a copy of the No-Dong, but was said to have been enhanced over the last two years to reach a range of 1,380 kilometers, Middle East Newsline reported.

The intelligence sources said Iran was said to have transferred missile expertise that was used in its Shihab-3 intermediate-range missile program.

North Korea's No-Dong was believed to have a range of 1,200 to 1,500 kilometers. But the only test of the No-Dong was in 1991 and the missile was said to have reached a range of 565 kilometers.

U.S. officials said North Korea was certain to offer for export its improved No-Dong. They said the most interested clients would be Iran and Syria.

"It seems to me they've demonstrated a willingness to export anything," Defense Secretary Donald Rumsfeld told an Asian security conference in Singapore on June 5. "And so to the extent they have the capabilities that they have indicated they have, reasonable people in the world have to assume they'd be willing to sell or use most of those capabilities."

Iranian officials said the Shihab-3 was now capable of reaching a range of 1,700 kilometers.