North Korean leader Kim Jong-un stressed the need to "exponentially" increase the number of the country's nuclear arsenal, saying South Korea has emerged as an "undoubted enemy," Pyongyang's state media reported Sunday.

He delivered the message during a plenary meeting of the ruling Workers' Party of Korea that ended the previous day. It was held to set Pyongyang's major policy directions for the new year.

In a situation where South Korea has become "our undoubted enemy, it highlights the importance and necessity of a mass-producing of tactical nuclear weapons and calls for an exponential increase of the country's nuclear arsenal," Kim was quoted as saying by the Korean Central News Agency in an English dispatch.

He also called for efforts to develop new intercontinental ballistic missiles and put a spy satellite into orbit as early as possible, according to the KCNA.

In an indication that the regime will continue its provocations in 2023, Kim laid out new goals for strengthening the country's military power for the new year Tuesday at the WPK meeting.

The North fired around 70 ballistic missiles last year, the most in a single year, including the Nov. 18 firing of a Hwasong-17 intercontinental ballistic missile.

In December, North Korea tested a high-thrust solid-fuel rocket engine for a "new-type strategic weapon system," a move seen as developing a solid-propellant ICBM capable of reaching the US mainland.

The North conducted a "final-stage" test for the development of a military spy satellite with a plan to complete preparation for the project by April next year. It also flew five drones across the South last week in its first such intrusion in five years.

At the party meeting, Kim vowed to strengthen nuclear force, stressing that the regime could use its nuclear arsenal if it comes under attack.

"Our nuclear force considers it as the first mission to deter war and safeguard peace and stability and, however, if it fails to deter, it will carry out the second mission, which will not be for defense," he said.

In a separate dispatch, the KCNA said the North fired "super-large" caliber artillery shots on Saturday and Sunday.

The North test-fired three rounds of shells from the launcher in its performance test on the final day of 2022, and a long-range artillery military unit fired one shot toward the East Sea on the following day.

In a ceremony to present the 600-mm rocker launcher to the WPK's plenary meeting, Kim called it an "offensive weapon" capable of carrying tactical nuclear warheads that could put the entire South Korea within its range, the KCNA said.

The North's leader called for all-out efforts to produce powerful weapons to "overwhelm" the United States and South Korea. (Yonhap)