North Korea appears to be preparing to launch its second military spy satellite into space, South Korea's military said on Friday, as animosities remain high over the North's continued weapons tests.

Last November, North Korea placed its first military reconnaissance satellite into orbit as part of its efforts to build a space-based surveillance network to deal with what it calls US-led military threats.

North Korean leader Kim Jong Un later told a key governing party meeting that his country would launch three additional military spy satellites in 2024.

On Friday, South Korea's military told local reporters at a background briefing that it detected signs that North Korea is engaging in activities believed to be preparations to launch a spy satellite at its main Tongchangri launch facility in the northwest. The military said South Korean and US intelligence authorities are closely monitoring the North Korean moves.

The contents of the briefing were shared with foreign media outlets including The Associated Press. The South Korean military didn't immediately explain exactly what North Korean activities were spotted in the Tongchangri area.

After launching its Malligyong-1 spy satellite on November 21, North Korea said it had transmitted imagery of key sites in the US and South Korea, including the White House and the Pentagon. But it hasn't released any photos, prompting widespread doubts about the capacity of its satellite.

In recent months, North Korea has extended its run of missile tests to expand its weapons arsenal. Analysts say North Korea likely thinks a larger arsenal would increase its leverage in future diplomacy with the United States.

Last week, South Korea said North Korea fired suspected multiple short-range ballistic missiles off its east coast. North Korea later said it tested a tactical ballistic missile with a new autonomous navigation system.