(CNN) -- Kim Jong Un has assumed "the supreme commandership" of the North Korean army, state media reported Saturday. 
 
 The power was transferred to him on October 8 at the behest of his father, Kim Jong Il, who died this month, said the state-run Korean Central News Agency. 
 
 The announcement came a day after prospects for a shift in relations on the Korean peninsula were dashed when North Korea said a change in leadership would not mean a change in policy. 
 
 "We solemnly declare with confidence that the South Korean puppets and foolish politicians around the world should not expect any change" from North Korea, the country's National Defense Commission said in a statement reported by KCNA. 
 
 That statement came after two days of elaborate ceremonies in Pyongyang that honored Kim Jong Il and underlined the rise of his son and chosen successor, Kim Jong Un, to the position of "supreme leader" of the secretive state. 
 
 The nuclear-armed North "will have no dealings with the Lee Myung-bak group of traitors forever," the statement said in an English-language version of the KCNA report. Lee is the South Korean president. 
 
 South Korea's Unification Ministry expressed disappointment. 
 
 "The ministry finds today's statement regretful," it said. "However, the ministry's basic principle towards easing tensions in inter-Korean relations and resolving problems through dialogues remains still. The ministry hopes North Korea to regain stability in the near future and present constructive attitude." 
 
 The North criticized the South Korean government's decision to allow only a select group of private citizens to visit Pyongyang to pay their respects to Kim Jong Il, whose death was announced last week. 
 
 Lee's government's "show of enmity" toward North Korea "culminated in its act of blocking south Koreans who wanted to visit Pyongyang to mourn the demise of leader Kim Jong Il," the statement said. 
 
 Seoul allowed a group of South Koreans, including a former first lady and a leading businesswoman, to travel to the North earlier this week to express condolences over Kim Jong Il's death. 
 
 That move, along with a number of other gestures like expressing condolences to the North Korean people, suggested a slight softening in Lee's government's hardline stance toward Pyongyang. 
 
 The North, though, did not appear to be impressed by those efforts, expressing anger Friday that more South Koreans weren't permitted to visit Pyongyang and that groups were allowed this week to release leaflets near the border criticizing North Korean leaders. 
 
 It also said that the South's decision to put its military on alert after Kim Jong Il's death created "a war-like atmosphere on the ground and in the seas and air." 
 
 In one of the more vehement passages of saber-rattling rhetoric, the defense commission warned of revenge over these perceived misdeeds. 
 
 "The veritable sea of tears shed by the army and people" of North Korea "will turn into that of retaliatory fire to burn all the group of traitors to the last one and their wailing into a roar of revenge to smash the stronghold of the puppet forces," the statement said. 
 
 Amid concerns over change in North Korean leadership, a top U.S. diplomat plans to travel to the region early next year in the first such talks since Kim Jong Il's death, the State Department announced Thursday. 
 
 Assistant Secretary for East Asian and Pacific Affairs Kurt Campbell will "discuss a range of important bilateral, regional and global issues" during his four days in China, South Korea and Japan. 
 
 The State Department statement specifically mentioned that the "latest developments related to North Korea" will be on the agenda. ||||| North Korea tells world to 'expect no change' 
 
 North Korea's new leader Kim Jong-un is an unknown quantity - making neighbours worried 
 
 North Korea has told the international community not to "expect any change" in the wake of Kim Jong-il's death. 
 
 The message came in a statement carried by state media and attributed to the powerful National Defence Commission. 
 
 "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," it said. 
 
 Kim Jong-il died on 17 December of a heart attack, state media said. 
 
 He had ruled North Korea since the death of his father Kim Il-sung in 1994. Under him funds were channelled to the military and North Korea conducted two nuclear tests. 
 
 His son, Kim Jong-un, has been named "supreme leader of the party, state and army". 
 
 'Unforgivable' 
 
 North Korea's neighbours are watching to see whether the leadership change will affect Pyongyang's ties with the international community. 
 
 The impoverished communist state remains technically at war with South Korea and is isolated on the international stage because of its dire human rights record and pursuit of nuclear weapons. 
 
 Six-nation talks aimed at ending Pyongyang's nuclear ambitions - involving the two Koreas, China, the US, Russia and Japan - have been stalled for months. 
 
 The statement from the NDC - which is thought to be the country's top decision-making body - said North Korea would "never deal" with South Korean leader Lee Myung-bak. 
 
 Mr Lee has angered Pyongyang by linking the provision of aid to progress on denuclearisation. 
 
 The NDC also criticised Seoul's "unforgivable" decision to allow only two non-official delegations to cross the border to pay their respects to Mr Kim. 
 
 Diplomatic flurry 
 
 Amid regional concern, the US is to send one of its top diplomats to East Asia to discuss the situation in North Korea. 
 
 Kurt Campbell will hold talks in Beijing, Seoul and Tokyo from 3-7 January, the State Department said. 
 
 Mr Campbell, who is the Assistant Secretary for East Asian and Pacific Affairs, will be the most senior US official to visit the region since Kim Jong-il died. 
 
 The US and South Korean defence chiefs, meanwhile, spoke for 20 minutes about issues on the Korean peninsula on Thursday. 
 
 The two "shared the view that peace and stability on the Korean peninsula is our overarching priority and agreed to maintain close co-operation and co-ordination in the weeks and months ahead", the Pentagon said in a statement. 
 
 On Thursday North Korea held a national memorial service for Kim Jong-il, ending the period of mourning. 
 
 Hundreds of thousands of North Korean troops and citizens lined up for the ceremony in Pyongyang's main square. 
 
 Top party and military officials hailed Kim Jong-un, the young and politically inexperienced new leader, in front of the huge crowd.
– The passing of Kim Jong Il won't change anything in North Korea, the country announced today in quite the blustery manner. "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," officials said in a statement, the BBC reports. The North "will have no dealings" with South Korea president Lee Myung-bak's "group of traitors forever." The statement, released by the National Defense Commission, hammered the South for its "show of enmity" that "culminated in its act of blocking South Koreans who wanted to visit Pyongyang to mourn the demise of leader Kim Jong Il." The South let just a few citizens head north following Kim's death, but the move doesn't seem to have appeased the North: Officials said Seoul had created "a war-like atmosphere" by putting its military on alert after the leader's death. North Korea's "sea of tears" will become "retaliatory fire to burn all the group of traitors to the last one," the statement said, according to CNN.