North Korea threatened Monday to unleash nuclear attacks against South Korea and the U.S. over Washington's plans to install an advanced missile system in South Korea and alleged rumors of a U.S.-led regime change effort against Pyongyang.

The statements came from two state-run sources, Minju Chonson and the Korean Central News Agency (KCNA). In the former piece, the official government newspaper said the U.S. delivery Tuesday of the Terminal High Altitude Area Defense (THAAD) missile system to South Korea turned the country into "an outpost of nuclear war." The U.S. has argued the defense apparatus is necessary to defend Seoul from the military and possibly nuclear threat from Pyongyang; however, North Korea and other critics of Washington have accused the U.S. of jingoism and provoking the already tense inter-Korean conflict.

"The United States will get the opportunity to deliver preventive strikes at any time on the territories of Russia and China, which are absolutely against its deployment now," the newspaper wrote of THAAD, which was scheduled to be operational within the next couple of months.

Read: Is US At Fault For North Korea Nuclear Threats?

Threats also came Monday from Pyongyang's official news outlet, KCNA. The outlet published a commentary titled, "U.S. Slightest Misjudgment of DPRK Will Lead It to Final Doom" on its English-language website, using an acronym for the country's full name — the Democratic People's Republic of Korea. The article blasted U.S. media outlets such as Voice of America, CNN and the Wall Street Journal that have run articles referencing alleged White House plans to overthrow North Korean leader Kim Jong Un and his government.

The article referenced U.S-based organizations and individuals such as the Council of National Interest and the U.S. Council on Foreign Relations, which have warned against using military force against North Korea. The commentary warned Pyongyang would answer any military action with a full-scale nuclear attack.

"Now that the U.S. started dangerous nuclear war drills again, the DPRK has no option but to counter it with the toughest measures for bolstering the nuclear force as it had already declared," the article read. "If even a single shell is fired into the territory in which the sovereignty of the DPRK is exercised, the bases of aggression and provocation will be reduced to such debris that no living thing can be found."

Read: 5 Years Of Kim Jong Un: What Has He Done For North Korea?

Experts have estimated North Korea's arsenal contains more than 1,000 missiles, some of which may be capable of reaching as far as the U.S. Pyongyang has also conducted at least five nuclear tests; however, the country's technological capability to miniaturize the weapons of mass destruction and attach them to existing projectiles has been subject to doubt. Pyongyang has regularly threatened to destroy its southern rival and defectors have claimed the country's reclusive, authoritarian leadership could wipe out Los Angeles with a nuclear strike.