NKorea hails 'invincible' army, warns of conflict

North Korean leader Kim Jong-Il has hailed his troops as "invincible" as state media on Sunday warned of a possible military conflict with South Korea amid heightened tensions.

Kim expressed confidence in his soldiers' ability to "shatter any surprise invasion of the enemy at a single blow" as he inspected an army unit, the North's official Korean Central News Agency (KCNA) said.

"The KPA (Korean People's Army)... has grown to be the invincible revolutionary ranks all members of which devotedly defend the Party and the leader," it quoted Kim as saying, without giving a date for the visit.

The KCNA dispatch came days after North Korea scrapped all political and military agreements with the South, further raising tensions between the two sides, which technically remain at war as the 1950-1953 Korean War ended without a peace treaty.

"To our nation in an armistice, confrontation means an escalated tension which could lead to an inescapable and unavoidable military conflict and war," Rodong Sinmun, the North's ruling communist party paper, said Sunday.

Rodong then warned of the South's "destruction" if Seoul keeps ignoring warnings from the North.

Accusing the South of pushing relations to the brink of war, the North announced Friday that all political and military agreements would be nullified, including one covering their Yellow Sea border -- the scene of bloody naval clashes in 1999 and 2002.

Hours later, South Korean President Lee Myung-Bak vowed to stick to what Pyongyang has called a "confrontational" policy on North Korea.

Lee, who took office a year ago, rolled back the "sunshine" engagement policy of his liberal predecessors, linking Seoul's economic assistance to Pyongyang's nuclear disarmament efforts.

South Korea stepped up its border monitoring and vowed to respond firmly to any violation, but said no unusual activities had been detected.

US State Department acting spokesman Robert Wood said the "distinctly not helpful" would not affect six-party talks aimed at scrapping Pyongyang's nuclear weapons programmes.

Pyongyang signed a deal with its five partners in 2007 calling for its nuclear weapons to be scrapped in return for aid, normalised relations with the United States and Japan and a formal peace pact on the Korean peninsula.

But the negotiations, which involve the two Koreas, the United States, China, Japan and Russia, are deadlocked as North Korea, which tested a nuclear device in 2006, baulks at a written agreement detailing ways to verify nuclear disarmament.