PYONGYANG, North Korea (AP) — North Korea warned the world Friday there would be no softening of its position toward South Korea’s government after Kim Jong Il’s death as Pyongyang strengthened his son and heir’s authority with a new title: Great Leader.

North Korea’s powerful National Defense Commission said that the country would never deal with South Korean President Lee Myung-bak, a conservative who stopped a no-strings-attached aid policy toward the North in 2008.

The stern message also said North Korea was uniting around Kim Jong Un, referring to him for the first time with the title Great Leader — previously used for his father — in a clear message of continuity. It was the latest incremental step in a burgeoning personality cult around the son following the Dec. 17 death of Kim Jong Il.

The younger Kim on Thursday was pronounced Supreme Leader of the ruling party, military and people at a massive public gathering on the final day of official mourning for his father.

The top levels of government appear to have rallied around Kim Jong Un, who is in his late 20s, in the wake of his father’s death. Still, given his inexperience and age, there are questions outside North Korea about his leadership of a nation engaged in delicate negotiations over its nuclear programme and grappling with decades of economic hardship and chronic food shortages.

“We declare solemnly and confidently that the foolish politicians around the world, including the puppet group in South Korea, should not expect any change from us,” the National Defense Commission said. “We will never deal with the traitor group of Lee Myung-bak.”

In a bellicose voice, a female news anchor for state TV read the National Defense Commission statement, saying the “evil misdeeds” of the Lee administration reached a peak when it prevented South Koreans from visiting North Korea to pay respects to Kim Jong Il, except for two delegations led by a former first lady and a business leader, both of whose husbands had ties to North Korea.

North Korea had said foreign official delegations would not be allowed at the funeral but that it would welcome any South Koreans who wanted to travel to pay respects to Kim.

“Even though we lost Kim Jong Il, we have the dear respected Kim Jong Un,” Kang Chol Bok, a 28-year-old officer of the Korean People’s Internal Security Forces, told The Associated Press. “We will turn our profound sorrow into strength and courage.”

The North’s statement is a warning for Seoul not to take the new leadership lightly, said Koh Yu-hwan, a North Korea expert at Seoul’s Dongguk University.

“It is also raising the stakes in case the South wants better relations so Pyongyang can extract greater concessions” during any later talks, Koh said. He added that it’s “too early to say the North is dashing hopes for reforms.”

While blasting the South’s leader, the North also offered a bit of hope for improved ties with the South, saying it “will continue to push hard toward the path of improved relations.”

But it added that any better ties won’t be “based on the deceitful ploys South Korea is employing by mixing ‘toughness’ and ‘flexibility.’” Seoul has signaled a change in its approach toward Pyongyang in recent months, saying it will be more flexible in dealing with the North.

South Korea’s Unification Ministry will maintain its North Korea policy and not react to every statement out of Pyongyang, according to a ministry official who declined to be identified citing the sensitivity of the relations between the countries.

On Thursday, a somber Kim Jong Un stood with his head bowed at the Grand People’s Study House, overlooking Kim Il Sung Square, named for his grandfather, who founded modern North Korea. A huge crowd of mourners gathered below.

Kim Jong Un was flanked by top party and military officials, including Kim Jong Il’s younger sister, Kim Kyong Hui, and her husband, Jang Song Thaek, who are expected to serve as mentors of their young nephew.

“The father’s plan is being implemented,” Ralph Cossa, president of Pacific Forum CSIS, a Hawaii-based think tank, said of the transfer of power. “All of these guys have a vested interest in the system and a vested interest in demonstrating stability. The last thing they want to do is create havoc.”

Titles are important in North Korea and part of the myth-building surrounding the Kim family legacy.

Kim Il Sung, the country’s first and only president, retains the title Eternal President even after his death.

Kim Jong Il held three main positions: chairman of the National Defense Commission, general secretary of the Workers’ Party and supreme commander of the Korean People’s Army. According to the constitution, his position as chairman of the National Defense Commission made him Supreme Leader of North Korea.

Kim Jong Un was made a four-star general last year and appointed a vice chairman of the Central Military Commission of the Workers’ Party. Since his father’s death, North Korean officials and state media have given him a series of new titles: Great Successor, Supreme Leader and now Great Leader.