The case of two North Korean fishermen, who murdered 16 compatriots before they sought asylum, has become a political minefield in the South.

Australia this month made an initial $500 million payment toward its purchase of U.S.-made nuclear submarines.

North Korea has condemned the "arrogance" of the United States and vowed to "counter enemy strategic threats with our own strategic means." Pyongyang made this statement on Friday as the regime continues to criticize the close cooperation between Washington and Seoul.