North Korean leader Kim Jong Un has attended a ceremony for the launch of a "new multi-purpose destroyer”.

The 5,000-tonne warship was equipped with the "most powerful weapons" and built "within 400-odd days perfectly with our own strength and technology," Jo Chun Ryong, a secretary in the ruling Workers' Party, was quoted as saying by state media KCNA.

In a speech from the launch, Kim, said the warship would be handed over to the navy and go into service early next year.

A view of a "new multipurpose destroyer," in Nampo, North Korea. – Reuters

The launch took place on Friday at the military shipbuilding dockyard of Nampho, and marked a new era of the "great Kim Jong Un-style fleet building," KCNA said quoting Vice-Admiral Pak Kwang Sop. The ship was graded as the "Choe Hyon-class" named after anti-Japanese revolutionary fighter Choe Hyon, the report added.

Earlier this month, Reuters reported that North Korea's new class of warship was able to accommodate dozens of vertical launch cells to carry missiles its military has already developed, citing analysis of a satellite image.

Kim also said strong pre-emptive attack capabilities were the most "convincing war deterrent" and that there was no limit to the scope of such attacks.

"The security environment of our country is very serious right now," the leader was quoted as saying.

He also thanked the workers and technicians for building the new destroyer, which was "true to the party's line of strengthening the naval forces," according to KCNA.

Kim also said that the United States was deploying strategic assets in the Korean Peninsula on a regular basis.

The B-1B was used in a joint military drill between South Korea and the U.S. earlier this month alongside fighter jets, according to Seoul's defence ministry.

B-1B bombers have featured regularly in joint military exercises in recent years. North Korea has long condemned the drills as a rehearsal for war. Seoul says they are purely defensive.