The United States on Tuesday called North Korea a "criminal state" and said its threat of military action amounted to more of the "provocative behavior" it has engaged in since last year.

North Korea's ambassador to the UN Sin Son Ho warned Tuesday that Pyongyang would take military action if the United Nations condemns the Stalinist regime over the March 26 sinking of a South Korean warship, the Cheonan.

"That sounds like the same kind of provocative behavior that has characterized North Korea unfortunately since early 2009," State Department spokesman Philip Crowley told reporters when asked for comment.

In April last year, North Korea launched a long-range rocket, attracting UN condemnation. It then bolted six-country nuclear disarmament negotiations. And in May, North Korea staged its second nuclear test, sparking tougher UN sanctions.

"What we need from North Korea is accountability," Crowley said.

"We're lookng for North Korea to change its unacceptable behavior, to cease belligerent actions," he said.

"The last thing we want to see is further tension in the Korean peninsula," he added.

Tensions on the Korean peninsula are high after a multinational investigation said last month a submarine from the North torpedoed the 1,200-tonne Cheonan near the disputed Yellow Sea border, killing 46 sailors.

Pyongyang has angrily denied any responsibility, and on Saturday the general staff of the Korean People's Army said it would attack loudspeakers set up by Seoul to broadcast cross-border propaganda.

Crowley also said it was "characteristic" of North Korea when asked to comment on a South Korean news report that Pyongyang on Saturday broadcast a pirate recording of Friday's opening FIFA World Cup match in South Africa.

"They could have normal relationships with their neighbors, they could enter into normal transactions with their neighbors, but they choose, rather than doing so, to try to steal or pirate the World Cup signal," he said.

"North Korea is a criminal state," Crowley said, using unusually harsh words for the communist state.

In Kuala Lumpur, Asia's broadcasting union said Tuesday that North Korea has secured legal rights to air World Cup matches live, denying the communist state had pirated a recording of the opening fixture.