Pyongyang's state-controlled news agency KCNA issued the statement the same day it denounced the United States for waging "wars of aggression" to eliminate international terrorism.
Describing the future training at sea as a "drill to invade the North," Pyongyang threatened destruction if the exercises, involving missile interception, take place as scheduled.
North Korea's Workers' Party newspaper Rodong Sinmun stated the South Korean government is responsible for the crisis on the peninsula and accused Seoul of treason, or collaborating with foreign powers.
The USS Ronald Reagan, the biggest U.S. warship based in Asia, was recently allowed to dock in Hong Kong as tensions have prevailed following a series of North Korea missile provocations and the sixth test of a nuclear device at Punggye-ri.
Rear Adm. Marc Dalton said, "The United States has been very clear about leveraging all options in order to get North Korea to change its path."
Dalton also described U.S. alliances with Japan and South Korea as "ironclad."
Yonhap TV reported Friday that Eom Hyun-sung, chief of South Korea naval operations, recently inspected South Korea's Aegis destroyer for preparedness.
The warship is deployed in the East Sea, also known as the Sea of Japan.
KCNA denounced the United States following the meeting of the United Nations' Sixth Committee on measures to eliminate international terrorism.
North Korea claimed the United States uses accusations of terrorism to "change regimes" or target countries.
Pyongyang charged the CIA with attempting to target the North Korean leadership through the use of biochemical weapons.