By Alex Jensen
SEOUL
South Korea vowed Friday to "strongly retaliate against any kind of North Korean attacks," a day after a dramatic escalation in tensions on the peninsula.
The message, announced publicly by Seoul's defense ministry, came after the reclusive North threatened to take military action unless the South abandons an ongoing psychological warfare campaign by 5 p.m. (0800GMT) Saturday.
Loudspeakers blaring information from the outside world were strategically placed by South Korea nearly two weeks ago, in response to its conclusion that Pyongyang was behind Aug. 4 landmine explosions in the southern portion of the Demilitarized Zone that has separated the sides since they reached an uneasy truce in 1953.
North Korea had apparently had enough when it opened artillery fire along the western border Thursday, albeit without causing damage -- but after the South responded with its own shells, Pyongyang denied starting the exchange.
Following the North's ultimatum delivered shortly after the shelling, South Korean Defense Minister Han Min-koo admitted that Seoul is taking the threat seriously.
"There is a possibility of North Korea launching provocations of a certain kind after 5:00 p.m. tomorrow," Han said.
The South has so far refused to switch off its broadcasts, including criticism of the North's dictator Kim Jong-un.
A Seoul government source also revealed Friday that North Korea is getting ready to launch ballistic missiles.
"The North is showing signs of lifting off a Scud missile near Wonsan and a Rodong missile in North Pyeongan Province," the source said, according to local news agency Yonhap.
Either would be banned under United Nations resolutions.
Earlier in the day, North Korea's state media reported that Kim Jong-un had ordered troops to be fully prepared for a "quasi-state of war."
