South Korea blared propaganda broadcasts into North Korea after a six-year halt and Pyongyang said its troops were bracing for war as tensions spiked on the divided peninsula over the deadly sinking of a warship.
One Seoul-based monitoring agency reported Tuesday the North's leader had ordered its 1.2 million-member military to get ready for combat after South Korea blamed the North for a March 26 torpedo strike that sank the warship Cheonan and killed 46 sailors. South Korean officials could not immediately confirm the report.
The South's restarting of psychological warfare operations — including radio broadcasts into the North and placing loudspeakers at the border to blast out propaganda — were among measures the government announced Monday to punish Pyongyang. The South is also slashing trade and denying permission to North Korean cargo ships to pass through South Korean waters.
A team of international investigators concluded last week that a torpedo from a North Korean submarine tore apart the Cheonan. The sinking was the South's worst military disaster since the 1950-53 Korean War, which ended with an armistice, not a peace treaty.
The North flatly denies involvement and has warned such retaliation would mean war. It has threatened to destroy any propaganda facilities installed at the heavily militarized border.
On Tuesday, the North's military claimed dozens of South Korean navy ships violated the countries' disputed western sea border earlier this month and threatened to take "practical" military measures in response, according to the official Korean Central News Agency.
South Korea's military had no immediate response other than to say that North Korea routinely makes similar accusations.
North Korea is already subject to various U.N.-backed sanctions in response to its nuclear weapons and missile programs. The latest steps announced by Seoul over what was are seen as among the strongest it could take short of military action.
The U.S. has thrown its full support behind South Korea's moves and they are planning two major military exercises off the Korean peninsula in a display of force intended "to deter future aggression" by North Korea, the White House said. The U.S. has 28,500 troops in South Korea.
South Korea also wants to bring North Korea before the U.N. Security Council over the sinking. U.N. Secretary-General Ban Ki-moon said Monday he expects the Security Council to take action against North Korea, but China — North Korea's main ally and a veto-wielding member of the Security Council — has so far done little but urge calm on all sides.
U.S. Secretary of State Hillary Rodham Clinton was in Beijing conferring with officials on a coordinated response. China's top nuclear envoy, meanwhile, huddled with South Korean officials in Seoul.
South Korea's military resumed radio broadcasts airing Western music, news and comparisons between the South and North Korean political and economic situations late Monday, according to the Joint Chiefs of Staff. The military also planned to launch propaganda leaflets by balloon and other methods Tuesday to inform North Koreans about the ship sinking.
In coming weeks, South Korea also will install dozens of propaganda loudspeakers and towering electronic billboards along the heavily armed land border to send messages enticing communist soldiers to defect to the South. The North warned Monday it would fire at any propaganda facilities installed in the Demilitarized Zone.
On Tuesday, North Korean state media cited the powerful National Defense Commission as saying the North's soldiers and reservists were bracing to launch a "sacred war" against South Korea.
North Korea often issues fiery rhetoric and regularly vows to wage war against South Korea and the U.S. It put its army on high alert following a November sea battle with South Korea near where the Cheonan went down. The Koreas fought bloody maritime skirmishes in the disputed area in 1999 and 2002.
A North Korean monitoring group said Tuesday that North Korean leader Kim Jong Il last week ordered his military to get ready for combat.
Seoul-based North Korea Intellectuals Solidarity, citing unidentified sources in North Korea, said in a report that the order was read by Gen. O Kuk Ryol, a Kim confidant, and broadcast on speakers installed in each house and major public sites throughout the country Thursday, hours after the multinational report blaming Pyongyang for the sinking was issued in Seoul.
The South Korean Defense Ministry and the Joint Chiefs of Staff said they have not obtained any signs suggesting unusual activity by North Korea's military.
Park Sang-hak, a North Korean defector who has led a civilian leaflet campaign against Pyongyang, said his sources in North Korea told him they haven't heard about such a broadcast. Park also noted that Kim's messages are usually first reported by state media, such as the main Rodong Sinmum newspaper, before being broadcast through loudspeakers.
The report still rattled the country's financial markets. Stocks fell to their lowest close in more than three months and its currency, the won, slid to its weakest level against the dollar since last July before paring some losses.
In a nationally televised speech on Monday, South Korean President Lee Myung-bak vowed that North Korea will "pay a price corresponding to its provocative acts."
On Tuesday, media reports said South Korea has decided to call North Korea its "main enemy" in formal defense documents for the first time in six years.
South Korea began using the term in 1995, one year after a senior North Korean official threatened to turn Seoul into "sea of fire," but deleted that reference in 2004 amid warming ties.
Associated Press writers Sangwon Yoon and Kelly Olsen in Seoul contributed to this report.
© Copyright 2013 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.