SEOUL, South Korea — A technical glitch forced South Korea to abort liftoff of its first rocket into space Wednesday, delaying a launch that threatened to stoke tensions with North Korea even as Pyongyang joined in mourning a leader who pushed tirelessly for reconciliation.

The rival Koreas are eager to develop space programs, and had aimed to send satellites into space this year. In April, North Korea launched a three-stage rocket it claimed sent a communications satellite into orbit; some experts doubt the mission succeeded.

Washington, Tokyo and others called that launch a disguised test of long-range missile technology. The U.N. Security Council condemned the launch, saying it was a violation of resolutions banning North Korea from ballistic missile-related activity.

However, there have been recent signs of easing tensions — the North freed two imprisoned American journalists when former President Bill Clinton came to Pyongyang and met with leader Kim Jong Il. Later, the North freed a South Korean technician and agreed to resume some joint tourism and industry projects with Seoul.

And on Wednesday, New Mexico Gov. Bill Richardson met with two North Korean diplomats. Richardson called the meeting a "hopeful sign" of improving relations.

Yet as South Korea geared up for its rocket launch, North Korea warned it would be "watching closely" for the international response to Seoul's launch.

"Their reaction and attitude toward South Korea's satellite launch will once again clearly prove whether the principle of equality exists or has collapsed," a spokesman for the Foreign Ministry told North Korea's official news agency.

South Korea's launch was called off less than eight minutes before the scheduled liftoff, senior Science Ministry official Lee Sang-mok said. The two-stage rocket, built with Russian help, would have been South Korea's first satellite launch from its own territory.

South Korean and Russian scientists were investigating the malfunction that halted the launch, and Russian scientists believed another attempt could occur within days, Lee said. He said a high-pressure tank that helps operate valves in the launch vehicle may have been the problem.

Despite the North's objections, U.S. and South Korean officials say the rocket launches cannot be compared, maintaining that South Korea has carried out the process transparently, and for peaceful purposes, while the North has not abided by its international commitments.