Kim has been inspecting field training of troops at a major military operations base.
North Korea's state-run television says he made the remark after a recent ICBM launching drill.
State media reports Pyongyang would respond to any US interference in space by eliminating the viability of US spy satellites.
"Comrade Kim Jong Un liked it."
Kim Jong Un called for a boost in weapons production and expansion of military drills.
The US military believe the soldier is in custody in North Korea.
Kim Jong Un said it would bolster strategic cooperation on their shared goal of building a powerful country.
It comes after the US called for a UN meeting to discuss North Korea's attempt to put its first spy satellite in orbit.
North Korea fired two short-range ballistic missiles into the sea off its east coast on Tuesday, South Korea's military said.
