North Korea warned the world today there would be no softening of its position toward South Korea's government after Kim Jong Il's death.

The warning came as Pyongyang strengthened his son and heir's authority with a new title: Great Leader.

North Korea's powerful National Defence 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 step in a growing personality cult around the son following the December 17 death of Kim Jong Il.

The younger Kim 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 program 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 Defence Commission said. "We will never deal with the traitor group of Lee Myung-bak."

A female news anchor for state TV read the 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.