South Korea ? South Korean President Lee Myung-bak stressed today the need to bolster military readiness and sternly respond to North Korea over the deadly sinking of a warship, or risk more such provocations.

South Korea has taken a slew of punitive measures against North Korea — including resuming propaganda operations — after blaming Pyongyang for torpedoing the South Korean warship Cheonan in March. Forty-six South Korean sailors died.

North Korea flatly denies the allegation and has warned any retaliation would trigger war. The country’s military said Saturday it would launch an all-out strike against any South Korean propaganda facilities at the border such as loudspeakers and could even turn Seoul into “a sea of flame.”