Kim Yo-jong, the powerful sister of North Korean leader Kim Jong-un, said that North Korea is ready to take overwhelming action against the military activities of South Korea and the U.S.

The younger Kim issued the warning in a statement carried by the North's state-run Korean Central News Agency on Tuesday, noting that Pyongyang is closely watching the military activities of South Korea and the U.S., ready to act swiftly and overwhelmingly at any time.

Claiming that the regime’s strategic weapons tests pose no risk to the safety of neighboring countries, Kim said a military response by the U.S. in the form of a missile interception in waters or airspace outside its jurisdiction will be considered a declaration of war against the North.

Kim added that the allies should refrain from actions that further aggravate the situation.

The warning comes amid the increasingly frequent deployments of U.S. strategic assets to the Korean Peninsula, most recently with an air drill over the Yellow Sea on Monday that included the participation of a long-range B-52H Stratofortress bomber.