"As of now, inter-Korea relations enter a state of war and all matters between the two Koreas will be handled according to wartime protocol," the North said in a government statement carried by the Korean Central News Agency.

"The long-standing situation of the Korean peninsula being neither at peace nor at war is finally over," the statement said, adding that any US or South Korean provocation would trigger a "full-scale conflict and a nuclear war".

This declaration came after the NoKor leader ordered missile units to prepare to strike US mainland and military bases, so as to "settle accounts" after US stealth bombers flew over South Korea.

Both China and Russia called for calm Friday, with Russian Foreign Minister Sergei Lavrov voicing particular concern.

"We can simply see the situation getting out of control, it would spiral down into a vicious circle," Lavrov told reporters at a news conference.

The United States said it took the announcement "seriously", even though it followed a familiar pattern, while South Korea largely dismissed it as an old threat dressed in new clothing. - ABS-CBN news

Revisiting the Island that was shelled by Nokor in 2010