Pyongyang has vowed a tough response to any military action from the US after it sent warships to waters off the Korean Peninsular.
Washington has dispatched the USS Carl Vinson aircraft carrier and its battle group to the region for US-South Korea wargames.
Tensions on the divided peninsula were already high because of recent ballistic missile launches by North Korea.
Pyongyang sees the annual wargames as a dress rehearsal for invasion, while the North's missile launches violate UN resolutions.
"We will hold the US wholly accountable for the catastrophic consequences to be entailed by its outrageous actions," a spokesman for North Korea's foreign ministry said.
The statement comes after US Secretary of State Rex Tillerson said US missile strikes against a Syrian air base in retaliation for a chemical weapon attack carry a message for any nation operating outside of international norms.
He did not specify North Korea, but the context was clear enough.
"If you violate international agreements, if you fail to live up to commitments, if you become a threat to others, at some point a response is likely to be undertaken," Mr Tillerson said.
The North has long claimed the US is preparing some kind of assault against it and justifies its nuclear weapons as defensive in nature.
"This goes to prove that the US reckless moves for invading the DPRK have reached a serious phase of its scenario," the North's statement said.
"If the US dares opt for a military action, crying out for 'pre-emptive attack' and 'removal of the headquarters,' the DPRK is ready to react to any mode of war desired by the US."
North Korea's formal name is the Democratic People's Republic of Korea.
US navy ships are a common presence in the Korean region and are in part a show of force.
On Saturday, the Pentagon said a navy carrier strike group was moving towards the western Pacific Ocean to provide more of a physical presence in the region.
President Donald Trump's national security adviser, HR McMaster, described the decision to send the carrier group as "prudent".