March 30 - North Korea says enters "state of war" against South

North Korea said on Saturday it was entering a "state of war" with South Korea, but Seoul and its ally the United States played down the statement as tough talk.

Pyongyang also threatened to close a border industrial zone, the last remaining example of inter-Korean cooperation which gives the impoverished North access to $2 billion in trade a year.

The United States said it took Pyongyang's threats seriously but cautioned that the North had a history of bellicose rhetoric. Russia, another a permanent U.N. Security Council member, urged all sides to show restraint.

Tensions have been high since the North's new young leader Kim Jong-un ordered a third nuclear weapons test in February, breaching U.N. sanctions and ignoring warnings from North Korea's sole major ally, China, not to do so.

"From this time on, the North-South relations will be entering the state of war and all issues raised between the North and the South will be handled accordingly," a statement carried by the North's official KCNA news agency said.

"North Korea's statement today ... is not a new threat but is the continuation of provocative threats," the South's Unification Ministry, which handles political ties with the North, said in a statement.

North Korea has canceled an armistice agreement with the United States that ended the Korean War and cut all hotlines with U.S. forces, the United Nations and South Korea.