North Korea has vowed to resume its plutonium-fueled nuclear power projects, which yields weapons-grade plutonium. Tuesday morning's announcement, which comes amid escalating warlike rhetoric, raised concerns about North Korea acquiring more military-capable reactor material.

According to the Washington Post, North Korea made the announcement early Tuesday, stating that it would revive a Soviet-era  reactor. Due to its outdated technology, the Yongbyong nuclear power plant would produce enriched plutonium, a necessary component to nuclear weapons.

“Nuclear threats are not a game,” U.N. Secretary General Ban Ki-moon said to the Washington Post on Tuesday. “Aggressive rhetoric and military posturing only result in counteractions and fuel fear and instability. Things must begin to calm down, as this situation, made worse by the lack of communication, could lead down a path that nobody should want to follow.”

Ban, who is from South Korea, also added that he was “deeply troubled” by North Korea’s announcement. 

Reuters notes that Yongbyong is too dilapidated to effectively supply power to North Korea's increasingly obsolete electricity grid.

"It was a reactor that was nearing obsolescence with a cooling tower that wasn't functioning properly when it was blown up. It could mean they've been rebuilding quite a few things," Yoo Ho-yeol, North Korea specialist at Korea University in Seoul, told Reuters.

North Korea’s commitment to obtaining more weapons-grade plutonium is especially worrying considering the regime’s recent threats against both South Korea and the U.S. On Friday, North Korea claimed to be in a state of war with South Korea. It also has indicated it has a U.S. mainland strike plan.

The mounting saber-rattling by North Korea has been in part a response to a new round of U.N. sanctions imposed after a recent nuclear-weapons test. In light of North Korea’s threats, the U.S. has taken action to demonstrate its military capablity on the Korean Peninsula.

On Thursday, the U.S. flew two B-2 stealth bombers over South Korea and dropped inert ammunition as a part of a military exercise, Reuters reported. Earlier in the week, the U.S. conducted a similar exercise with a B-52 bomber.

North Korea denounced both exercises as hostile measures. After the first military exercise, North Korea reportedly took steps to ready its long-range artillery against strategic targets, such as U.S. bases throughout the Asia-Pacific region.