NORTH Korea told its military overnight to become "human rifles and bombs" to defend new leader Kim Jong-un and vowed an all-out push for prosperity, in a New Year message setting out policy goals.

"The entire army should place absolute trust in and follow Kim Jong-un and become human rifles and bombs to defend him unto death," an editorial in official newspapers said, a day after the late Kim Jong-il's youngest son was proclaimed the supreme military commander.

Kim visited a tank division on New Year's Day, the KCNA state news agency said, accompanied by his influential uncle Jang Song-thaek, military chief Ri Yong-ho and other military leaders.

"The whole party, the entire army and all the people should possess a firm conviction that they will become human bulwarks and human shields in defending Kim Jong-un unto death and follow the great party forever," the editorial said.

Kim, aged in his late 20s, was swiftly proclaimed the "great successor" after his father died December 17.

It was announced Saturday that he had been formally appointed supreme commander of the 1.2-million-strong military, the world's fourth largest.

Chinese president Hu Jintao, whose country is the North's main ally and economic prop, sent Kim "warm congratulations" on assuming the military leadership, KCNA reported yesterday.

North Korea, closing ranks behind its new leader, has warned the world not to expect policy changes and threatened South Korea for perceived disrespect during the 13-day mourning period for Kim.

Sunday's editorial vowed to "consolidate" the armed forces and called for the US to pull its 28,500 troops out of the South. But it said Pyongyang will "strive to develop relations of friendship with countries that respect our country's sovereignty."

The impoverished country has set the goal of becoming a "powerful and prosperous" nation this year. April 15 marks the 100th anniversary of the birth of late founding president Kim Il Sung, the current leader's grandfather.

"This year is the year when Kim Jong Il's plan for achieving prosperity will bear a brilliant fruit," the editorial said, calling for "an all-out drive to implement our party's grand strategy for achieving prosperity."

The annual editorial did not mention the country's nuclear weapons program, which has earned it international sanctions.

However, the editorial renewed the North's criticism of the South's conservative government, saying the "traitors" failed to respect the mourning for Kim.

Seoul expressed sympathy to the North's people but not its regime and allowed just two private mourning delegations to visit Pyongyang. The North has threatened unspecified retaliation against the South unless it apologises.