North Korean leader Kim Jong Il has put the Stalinist state's army on combat alert amid rising tensions after the March sinking of a South Korean warship was blamed on Pyongyang, a news report said on Tuesday.
A high-ranking official read Kim's orders on national television last week, South Korea's Economic Daily newspaper said, citing reports by North Korean refugees.
The order was issued after Seoul said Thursday that investigations had concluded that a torpedo fired by North Korea was responsible for the March 26 sinking of the corvette Cheonan, which killed 46 South Korean sailors.
Kim did not want war but North Korea was ready to repel any attack by the South, the orders said.
South Korean President Lee Myung Bak Monday announced far-reaching trade bans and said Seoul wanted the UN Security Council to discuss Pyongyang's "provocation", a move supported by Washington.
UN Secretary General Ban Ki-moon called Pyongyang's actions the "most serious provocation" in the troubled Korean Peninsula and indicated his support for measures by the Security Council.
The Pentagon, meanwhile, announced joint US-South Korean navy manoeuvres that are to focus on anti-submarine drills and interdicting vessels on the high seas.
Pyongyang routinely puts its troops on high alert during those manoeuvres.