North Korea warned rival South Korea and the rest of the world Friday that there would be no policy changes under new ruler Kim Jong Un.

A day after Pyongyang ended official mourning for longtime ruler Kim Jong Il, the North's powerful National Defense Commission sent a tough message to what it called “foolish politicians around the world.”

“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 stern message broadcast on state media said North Korea was uniting around “Great Leader” comrade Kim Jong Un following the recent death of his father.

The statement declared that the country would never deal with South Korean President Lee Myung-bak, a conservative, who has pursued a hard-line stance against the Stalinist North and that the people and military will rally around Kim Jong Un.

In Seoul, South Korean Unification Ministry spokesman Choi Boh-seon told reporters the Korean peninsula was now in a state of “growing mobility” after Mr. Kim's death.

“As North Korea's top leader died, the mobility in the Korean Peninsula's situation has heightened. The South Korean Unification Ministry's main focus next year is to closely monitor situation changes, and to deal with any changes flexibly, promptly and with initiative, based on our policies.”

Since Kim Jong Il's death on December 17, the world has been watching for any signs of change under the rule of his 28-year-old son.

North Korea declared Kim Jong Un supreme leader of the ruling party and military Thursday at a massive public memorial for the elder Kim.

The ceremony ended the country's period of mourning. Witnesses say trade, traffic and boat tourism between the North and the Chinese border city of Dandong returned to normal on Friday.