North Korea on Friday criticized the South Korean leader by name and reiterated its resolve to simultaneously develop its nuclear capability and economy, a goal that President Park Geun-hye has said is doomed to fail.

The North said that all efforts by Park and her cohorts to join forces with foreign powers and strive to denuclearize the North will only end in failure, according to a statement by the North's National Defense Commission.

It said such a move amounts to perpetrators "digging their own graves."

The remarks came after Park called on the North to give up its nuclear ambitions at the Armed Forces Day ceremony on Tuesday and stressed Seoul's firm commitment to developing strong defensive capabilities to deter threats from North Korean nuclear weapons and render them useless.

The defense commission added that the North Korean people and military will build a country that will be the envy of the world by following its own course of action and rules.

The powerful commission added that Pyongyang will move steadfastly forward with its line of simultaneously pushing forward with economic construction and building up its nuclear force, making clear it has no intention of desisting from its drive to own nuclear weapons.

This goal was first announced at the plenary session of the central committee of the ruling Workers' Party of Korea in March and had been mentioned intermittently to show the North's defiance against outside pressure.

In the statement, the North also blasted South Korea's president by saying she should first look at the "developments of the time" before making presumptuous comments and further warned that she is entering the path of a dictator.

The latest verbal attack is viewed by North Korea experts as being "unusually" intense, as the North usually attacks South Korea's government and ruling party and refer to Park as South Korea's chief executive, rather than by her name, when criticizing her. The North has only rapped the South Korean leader by name five times since she took office in late February, with the most recent taking place in July.

Related to the latest diatribe, Seoul's unification ministry, which is in charge of all inter-Korean relations, expressed deep regrets over Pyongyang's use of offensive language against the president and said such actions can only be viewed as being irrational.

"Countries do not verbally attack the leaders of other states using such language," said spokesman Kim Eui-do. He said in a formal statement that such behavior is not conducive to ongoing efforts to build trust amid difficult circumstances.

The official said that if the North truly wants improvements in South-North relations, it should show behavior based on respect.

He added that while the North mentioned developments taking place at present to criticize Park, it should really understand that the world wants it to give up its nuclear weapons and move to find ways to better feed its people.

"Building nuclear and long-range missiles do nothing to help alleviate the plight of ordinary North Koreans suffering from malnutrition," Kim emphasized.

Echoing the official line, Unification Minister Ryoo Kihl-jae told lawmakers earlier in the day that there are signs South-North relations have entered a cooling off period. He said a spike in criticism by Pyongyang and a lack of willingness to pursue measures that can increase cross-border contact were all indications.

However, he said that the government is firmly committed to providing humanitarian assistance to the North, even if it engages in nuclear tests, fires off missiles and threatens the South.

On the issue of the North Korean media outlets blaming the South for the lack of headway being made on pledges made at the

2007 summit meeting, another South Korean official pointed out that both sides need to work together on bilateral issues. He commented that the North has often not kept its word in deals reached.

Most recently, Pyongyang unilaterally postponed family reunions for people separated by the 1950-53 Korean War, citing provocations from the South.

The official, who declined to be identified, also said criticism by the North on the move by Seoul to not mention the creation of a Yellow Sea peace zone in its latest five-year inter-Korean development plan reflected "natural developments"

taking place at present. The zone was a prominent part of Seoul's North Korean policy under late South Korea President Roh Moo-hyun.

"Under current circumstances it may not be appropriate to touch on the issue," he said.

The zone was proposed to prevent another clash along the sea demarcation line that has witnessed several naval clashes in the past. (Yonhap News)