North Korea makes traffic ban threat in ship row

North Korea threatened today to block cross-border traffic and blow up any South Korean loudspeakers blasting propaganda northwards after a six-year suspension, as tensions soared over the sinking of a South Korean warship.

The dramatic deterioration in relations came as US Secretary of State Hillary Rodham Clinton visited Seoul on the final leg of a three-nation Asian tour which was dominated by the March 26 sinking blamed on a North Korean torpedo attack.