North Korea fired at least one ballistic missile toward the East Sea on Saturday, South Korea's military said, after Pyongyang has denied responsibility for last week's mine blast along the inter-Korean border. The Joint Chiefs of Staff (JCS) said it detected the launch at about 6:30 a.m. from the Wonsan area, without elaborating. "The South Korean military has stepped up surveillance for potential additional launches and is maintaining an all-out readiness posture while sharing relevant information with the United States and Japan," the JCS said in a notice. The latest launch came amid heightened inter-Korean tensions following the Sept. 21 blast of North Korean land mines inside the Demilitarized Zone (DMZ) separating the two Koreas. The incident left three South Korean soldiers injured, two of them seriously. The South Korean military has blamed North Korea for the mine blast, calling it a "blatant violation" of the armistice agreement. Seoul has also demanded apology from Pyongyang and urged it to halt border fortification work. North Korea denied its involvement in a statement issued