SEOUL, South Korea (AP) — South Korean soldiers fired 20 warning machine gun rounds Thursday, turning back North Korean soldiers apparently pursuing a comrade who had earlier dashed across the rivals' shared border, officials said. It is the fourth time this year a North Korean soldier has defected across the world's most heavily armed border.

South Korean military officials said they heard gunfire from the North after South Korea fired its warning shots, but it wasn't clear if the firing was retaliatory. Neither side immediately reported casualties.

North Korean soldiers occasionally flee ove...