China on Friday warned North Korea, its ally, and the United States to de-escalate tensions before the situation in the peninsula reached "an irreversible and unmanageable stage".
"We will respond to an all-out war with an all-out war and a nuclear war with our style of a nuclear attack", said Choe, widely seen by analysts as North Korea's No. 2 official.
It came a day after North Korea displayed almost 60 missiles - including what is suspected to be a new intercontinental ballistic missile - at a parade to mark the 105th birthday of its founder Kim Il-Sung.
The display included submarine-launched ballistic missiles, believed to be the same type of missile North Korea fired from land in February.
Choe Ryong Hae said that President Trump was guilty of "creating a war situation" on the Korean Peninsula by dispatching USA forces to the region.
The official added that if the United States shows any sign of "reckless" military aggression, Pyongyang is ready to launch a pre-emptive strike of its own.
The range of new hardware on display came as a bit of a surprise, and it's been interpreted as a show of force to the U.S. President Donald Trump, who has taken an aggressive tone against Pyongyang.
The official said the missile was not an intercontinental ballistic missile (ICBM), which North Korea has claimed to possess but has never successfully tested.More news: Nokia 6 Users To Get Android 7.1.1 Nougat Update
Sinpo, where the launch took place, is the site of a North Korean submarine base and where the North has tested the submarine-launched ballistic missile (SLBM) it is developing.
Goose-stepping soldiers and marching bands filled the square, next to the Taedonggang River that flows through Pyongyang, in the hazy spring sunshine, followed by tanks, multiple launch rocket systems and other weapons.
But if the parade signaled a readiness for war, North Korea has long insisted that its goal is peace - and survival - with the growing arsenal a way to ensure that the government in Pyongyang is not easily overthrown.
North Korea is under United Nations sanctions over its weapons programmes but has long wanted a rocket capable reaching the U.S. mainland.
So-called cold launches would also allow the missiles to be fired from silos.
North Korea also launched a long-range rocket a year ago that put a satellite into orbit, which Washington, Seoul and others saw as a banned test of missile technology. "If they start a nuclear war, we will respond with nuclear strikes".
All eyes are on the Trump administration's plans for North Korea, with concern growing since last week's USA missile strike in Syria, in response to a deadly gas attack.
The US, which has moved an aircraft carrier and several other warships towards the Korean peninsula, has previously warned its policy of "strategic patience" with North Korea is over.