North Korea broke off an agreement to halt testing of nuclear devices and long-range missiles after the U.S. canceled food assistance to the totalitarian regime following last week’s botched rocket launch.

North Korea is now “free” to take “necessary retaliatory measures” after the U.S. withdrew its offer of 240,000 tons of food, the Foreign Ministry said in a statement today carried by the official Korean Central News Agency.

It is also prepared to wage a “holy war” against South Korean President Lee Myung Bak’s government and would take “special action” against targets that could include central Seoul, an unidentified spokesman of the supreme command of the Korean People’s Army said in a separate statement carried by KCNA. The regime often issues statements threatening war.

The Obama administration pressed North Korea to cancel the April 13 launch of the rocket, which disintegrated minutes after liftoff, saying it would nullify the Feb. 29 accord to provide food in return for the suspension of nuclear and missile tests. South Korea said the result may lead new leader Kim Jong Un to compensate for the failure by testing a nuclear device.

“There will be a cooling-off period where the U.S. and North Korea exchange criticisms and shift blame on the other,” said Yang Moo Jin, a professor at the University of North Korean Studies in Seoul. “Depending on China’s role in that process, this could turn to dialogue or additional provocation by North Korea.”

’Bad Behavior’

The U.S. is abusing the United Nations Security Council by “imposing its brigandish demand,” the foreign ministry said, referring to the 15-member body’s censure issued this week. U.S. Ambassador Susan Rice is the council president this month.

North Korea’s statement is “not surprising, given their recent behavior,” U.S. State Department spokesman Mark Toner said in Washington. Asked whether the U.S. had information North Korea was preparing to test a nuclear device, he said, “there’s been this pattern of bad behavior, if you will. So we can’t preclude anything at this point.”

The Security Council’s April 16 statement called the launch a “serious violation” of existing resolutions that ban North Korea from using its ballistic missile technology. The council also said it would update its list of sanctioned goods.

The UN body moved more quickly than in the past to censure North Korea, and China’s approval signals that the Kim regime’s only ally “might be taking a firmer stance against the North,” Yang said. China is a permanent veto-wielding member of Security Council.

Debris Search Ends

The rocket, which was fired on April 13 to put a satellite into orbit, exploded shortly after liftoff over the Yellow Sea, scattering debris off the South Korean coast. A South Korean intelligence report warned a week ago that recent activity at the North’s Punggye-ri nuclear testing site is consistent with preparations for previous atomic device detonations.

South Korea yesterday called off a search for debris after four days of unsuccessful attempts to locate parts from the rocket due to murky waters and strong currents.

Kim Jong Un, who took power in December following the death of his father Kim Jong Il, used his first public speech on April 15 to say the world can’t threaten or blackmail North Korea’s “undefeated” 1.2 million-strong military.

Two UN resolutions are already in place after North Korea detonated atomic devices in 2006 and 2009. The measures call for stepped-up inspection of suspect air and sea cargo and seek to block funding for nuclear, missile and proliferation work.