A White House official said that the United States takes North Korean leader Kim Jong-un's efforts to advance sophisticated weapons systems "very seriously."

John Kirby, the National Security Council coordinator for strategic communications, made the remarks on Tuesday during a press briefing.

Kirby said that Washington takes the continued efforts by Kim to advance and develop sophisticated weapons systems and capabilities very seriously and that it is necessary for the U.S. to take such a stance.

The official continued to say that the U.S. also takes its alliance with South Korea very seriously, which is why U.S. President Joe Biden has added resources and capabilities and invested more in deepening the bilateral relationship with South Korea and the trilateral relationship with South Korea and Japan.

Kirby also expressed concerns about growing military ties between North Korea and Russia and the escalation in Kim’s rhetoric against South Korea and the U.S. 

In a briefing last month, Kirby said that there is a need to take such rhetoric seriously from a man in charge of a regime that continues to pursue the advancement of military capabilities including nuclear capabilities.