North Korea is "ready to sink" a US aircraft carrier heading for the peninsula, state media have said.
A commentary in the Rodong Sinmun newspaper warned that the USS Carl Vinson could be sunk "with a single strike".
A battle group headed by the Vinson is expected off the peninsula this week.
It was despatched by President Donald Trump amid a warning that US "strategic patience" over the North's nuclear ambitions had come to an end.
Tension also rose after a recent failed missile test by the North and a massive military parade showing off its latest hardware.
Sunday's commentary in Rodong Sinmun, the mouthpiece of the ruling Workers' Party, followed a feature on leader Kim Jong-un's inspection of a pig farm.
"Our revolutionary forces are combat-ready to sink a US nuclear-powered aircraft carrier with a single strike," the commentary read, saying that the attack on what it called a "gross animal" would be "an actual example to show our military's force".
State newspaper Minju Joson echoed this, warning the army would "deal merciless destructive blows at the enemies so that they would not come back to life again".
Rodong Sinmun was equally outspoken last week after US Secretary of State Rex Tillerson, on a tour of Asian nations, said the US was "reviewing all the status of North Korea, both in terms of state sponsorship of terrorism as well as the other ways in which we can bring pressure on the regime in Pyongyang".
Rodong Sinmun replied: "In the case of our super-mighty pre-emptive strike being launched, it will completely and immediately wipe out not only the US imperialists' invasion forces in South Korea and its surrounding areas but the US mainland and reduce them to ashes."
The North also threatened to strike Australia with nuclear weapons if it remained an ally of the US.
North Korea says its nuclear programme is defensive but it is trying to develop weapons small enough to put on ballistic missiles. There is no evidence yet it has done so or that it has missiles with the range to reach long-distance targets.
The Vinson battle group was conducting joint exercises with the Japanese navy in the Philippine Sea on Sunday.
Timeline of recent tensions
- 8 April: The US military orders a navy strike group to move towards the Korean peninsula
- 11 April: North Korea says it will defend itself "by powerful force of arms"
- 15 April: North Korea puts on a huge military parade - complete with missiles - to mark 105th birthday of the nation's founding president, Kim Il-sung. Meanwhile US Vice-President Mike Pence arrives in South Korea
- 16 April: North Korea conducts a rocket test, but it fails
- 17 April: Senior North Korean official tells the Eyes On Events the country will continue to test missiles "weekly" and Mr Pence warns North Korea not to "test" Donald Trump
- 18 April: It emerges the US Navy strike group was not heading towards North Korea when US officials suggested it was