The rocket launched by North Korea on August 31

Latest developments:

• No sign of satellite
• Missiles have high priority
• Iran, Pakistan are customers

From Military Affairs Correspondent Jamie McIntyre

WASHINGTON (CNN) -- U.S. officials say that North Korea may have been telling the truth when it claimed it launched a satellite last Monday, but that the launch's primary purpose was to test a new, long-range ballistic missile.

The officials also say that the attempt to put a satellite into space appears to have been unsuccessful.

North Korea claimed Friday that it launched a satellite aboard a multistage rocket.

But U.S. intelligence and defense sources say that while North Korea may have tried to launch a satellite in conjunction with its first test of a two-stage Taepo Dong 1 missile, there is no evidence of a North Korean satellite orbiting the Earth.

They say no radio transmissions have been detected and there have been no communications between North Korea and a satellite in Earth orbit.

Sources say the U.S. Space Command in Colorado Springs, Colorado, is capable of tracking objects as small as softballs.

U.S. officials are confident that the launch was simply the first test of one of two new ballistic missile systems under development in North Korea.

Missiles have high priority

The Taepo Dong 1 has an estimated range of up to 1,242 miles (2,000 kilometers), and is capable of carrying nuclear, biological or chemical warheads.

A longer-range version, the Taepo Dong 2, is expected to have a range of between 2,485 and 3,728 miles (4,000 and 6,000 km), far enough to reach Alaska.

Sources say that in last Monday's launch, the missile traveled about 950 miles, dropped its booster stage into the Sea of Japan, and then flew over Japan before splashing down 300 miles east of the Japanese island of Honshu.

U.S. officials theorize that North Korea, an exporter of military missiles, may have attempted to put a rudimentary satellite into orbit so that it could market its Taepo Dong 1 as a peaceful space-launch vehicle.

U.S. officials say there is no evidence that North Korea is planning a second test of the missile.

Despite economic and political problems, North Korea continues to give the development and sale of ballistic missiles, equipment and related technology high priority.

Iran, Pakistan are customers

The country has pursued an aggressive program since the 1980s and has steadily progressed from producing and exporting Russian-designed short-range ballistic missiles like the SCUD to developing medium- and long-range missiles.

Iran and Pakistan both tested ballistic missiles this year that were believed to have been based on North Korean technology and designs.