A North Korean long-range rocket launch in the next several weeks is technically possible but unlikely, experts here said Wednesday.

Although Pyongyang has political reasons to show increased activities in its missile test site, they said, pressing ahead with a high-stakes blast is a different matter.

"I believe it is technically possible for North Korea to again attempt to launch a multi-stage, Unha-3-type rocket during the December-January timeframe, but I have my doubts it will happen,"

Greg Thielmann, senior fellow at Arms Control Association, told Yonhap News Agency.

South Korean military intelligence sources said, based on satellite images shared by the U.S., North Korea appears to be preparing to shoot a long-range missile at its Sohae Satellite Launch Station near the border with China, a scene similar to that ahead of North Korea's rocket launch in April.

The U.S. State Department officially reiterated it would not talk about the intelligence-related matter.

U.S. military sources, however, were quoted as telling local media they have detected activity on the launch pad.

"There are political reasons that North Korea would want South Korea and the United States to believe a test was imminent,"

Thielmann said. "It would enhance Pyongyang's prestige and potentially serve as political leverage."

North Korea is apparently unnerved by Seoul's move to extend the range of its ballistic missiles up to 800 kilometers.

South Korea is also about to try again to put its own space rocket into orbit. Presidential elections will be held in South Korea on Dec. 19, with U.S. President Barack Obama to begin his second term the following month.

Thielmann raised doubts that the North will fire off a long-range rocket in the near future, citing "historical and technical reasons."

"First, the past four attempts have all occurred in the spring or summer, never in the middle of winter," he pointed out. "Second, a serious effort to explore the reasons for the failure of the first stage during the April 2012 launch would probably take more time than eight months to trouble-shoot and make appropriate corrections in design or quality assurance manufacturing procedures."

Because of the embarrassment of past failures, he added, North Korea is expected to maximize chances that the next launch would be successful.

"Rushing to meet a political requirement could well backfire,"

he said.

David Wright, co-director and senior scientist at the Union of Concerned Scientists, agreed.

"Preparing for a launch less than a year after a failure calls into question whether the North could have analyzed and fixed whatever went wrong," he said in a report posted on the Web site of the union.

The rocket fired by North Korea in April degenerated shortly after lift-off. In a highly unusual move, the reclusive communist nation announced the failure.

Wright, renowned for his expertise on missile technology, questioned Pyongyang's long-range missile capability.

"It has not test-flown a heatshield that would be needed for a long-range missile, and may not be able to build a small enough nuclear warhead for such a missile," he said.

He added Pyongyang would know its preparations will be seen and discussed in the west and they are intended to be a signal rather than signs of an imminent launch.

"In particular, the North has not yet announced splashdown zones for its launch as it did for its last two tests, so it may not have launch plans for the immediate future," he said.

South Korean officials remain cautious about the possibility of North Korea's missile launch anytime soon.

"As you know, North Korea is unpredictable when it comes to provocative acts," an official at the South Korean embassy in Washington said. "All we can say now is that we are keeping a close eye on it in cooperation with the U.S." (Yonhap News)