Pyongyang: North Korea on Friday said that US sanctions on its leader Kim Jong-un for human rights violations are a "declaration of war" and threatened to retaliate with the "toughest countermeasures" unless Washington withdraws them. The reaction comes in response to the measure announced on Tuesday by the US Treasury Department which includes Kim Jong-un for the first time together with ten other top North Korean officers on the Washington sanctions list for abuses of human rights, EFE news reported. "This is the worst hostility and an open declaration of war against (North Korea)," said the North Korean Ministry of Foreign Affairs in a statement reported by state-run news agency KCNA. "The US dared to challenge the dignity of (North Korea's) supreme leadership, an act reminiscent of a new-born puppy knowing no fear of a tiger," said Pyongyang which also accuses Washington of committing "the worst crime that can never be pardoned." The North Korean regime threatens to cut off all diplomatic channels between the two countries in the event that the US fails to withdraw the sanctions. The North Korean Foreign Ministry also warned that "Pyongyang will take the toughest countermeasures to resolutely shatter the hostility of the US as regards the fact that the latter's hostile policy has reached the worst phase of hurting the dignity of the former's supreme leadership." The US Treasury Department's report affects Kim Jong-un, ten North Korean officials and five entities of the country and caused the freezing of properties that they may have under US jurisdiction and prohibiting US citizens to engage in financial transactions with them.