SEOUL (Reuters) - North Korea said on Friday it was scrapping all accords with the South, the latest in a series of angry verbal attacks on its neighbor that some analysts say are more designed at grabbing the new U.S. government's attention.

One analyst said the latest rise in tension increased the chances of a military clash on the heavily armed border that has divided the two Koreas for more than half a century.

"There is neither way to improve (relations) nor hope to bring them on track," North Korea's KCNA news agency quoted the Committee for the Peaceful Reunification of Korea as saying.

South Korean officials were not immediately available for comment.

Impoverished North Korea has bridled at the hard-line policy of the year-old conservative government in the South which has ended a free flow of aid. Seoul has promised massive aid and investment only if Pyongyang is serious about giving up its nuclear weapons program.

But the isolated state has made clear it is not ready to sacrifice the little international leverage it has in the form of a nuclear threat, without first establishing diplomatic relations with the United States.

In recent months, it has all but closed the few border links with the South that were open, though a lucrative industrial park operated by Seoul just inside its border has remained open.

"First, all the agreed points concerning the issue of putting an end to the political and military confrontation between the north and the south will be nullified," KCNA quoted the committee as saying.

"Second, the Agreement on Reconciliation, Non-aggression, Cooperation and Exchange between the North and the South and the points on the military boundary line in the West Sea stipulated in its appendix will be nullified," it said.

Korea University professor Yoo Ho-yeol said the latest comments had three main aims: to pressure South Korean President Lee Myung-bak, scare the United States and to drum up political support at home.

North Korea had hinted in a New Year's message that it was willing to work with new U.S. President Barack Obama by saying it wanted good relations with countries that treated it in an amicable manner.

"The North probably believes that this type of thing is the most effective way of getting the upper hand with the U.S. ahead of negotiations by raising tension," Yoo said.

"What is worrying is that the possibility of a military clash is rising," Yoo said, pointing to the possibility of broader confrontation than naval skirmishes in 1999 and 2002.

The latest move follows comments by a U.S. national security official that the secretive state's leader, Kim Jong-il, appeared to have rebounded politically from his recent health scare and is making major decisions.

(Additional reporting by Jack Kim and Yoo Choonsik in Seoul and Randall Mikkelsen in Washington, Editing by Dean Yates)