North Korea has threatened to sink the San Diego-based aircraft carrier USS Carl Vinson, which was recently diverted to put it closer to the Korean Peninsula, it was reported Monday.
North Korea is the only country to have tested nuclear weapons in the 21st century, and such a step would be seen as a major provocation to United States forces in the area and South Koreans, who have placed their military on high alert.
Vice President Mike Pence said it would arrive "within days", but gave no other details.
The North also said the presence of the MI would create a "touch-and-go" situation on the peninsula, with Rodong Shinmun, the official newspaper of the ruling Workers' Party of Korea, writing on Monday, "If the enemies recklessly provoke the DPRK, its revolutionary armed forces will promptly give deadly blows to them and counter any total war with all-out war and nuclear war with a merciless nuclear strike of Korean style".
The Carl Vinson drills, expected to last several days, involve two Japanese warships, Japan's defence ministry said.
North Korea has conducted five nuclear tests, two of them a year ago, and is working to develop nuclear-tipped missiles that can reach the United States.
A North Korean state-run newspaper said that a single airstrike would take out the vessel.
Worry that North Korea could be preparing to conduct another nuclear test or launch more ballistic missiles has increased as it prepares to celebrate the 85th anniversary of the foundation of its Korean People's Army on Tuesday.
Trump has vowed to prevent North Korea from being able to hit the United States with a nuclear missile and has said all options are on the table, including a military strike.
NPR reported that the USS Carl Vinson's strike group is now in the Philippine Sea, where it's taking part in joint exercises with Japan's Maritime Self-Defense Force.
Mr Trump also spoke by telephone with Japanese Prime Minister Shinzo Abe. The statement, announced on North Korea's state-run Korean Central News Agency (KCNA), said: "The DPRK [Democratic People's Republic of Korea] is ready to react to any mode of war desired by the U.S".
Washington is sending a senior envoy on the nuclear standoff with North Korea to Tokyo this week for talks with his Japanese and South Korean counterparts. The paper quoted a Japanese military official as saying that the participating Japanese destroyers, Samidare and Ashigara, would "practice cruising in tactical formation and test communications procedures" with the US ships during the drill. If the "enemies show a slight provocation", the North said it would "liberate South Korea at a go and wipe out all the strongholds of the empire of evil beyond the Pacific".
However, the group said it was unclear whether the site was in a "tactical pause" before another test or was carrying out normal operations.