North Korea is feeling punchy. Its apparent nuclear test earlier this week outraged the West, and now, according to a South Korean newspaper citing an unidentified government official, U.S. spy satellites have detected steam over North Yongbyon's nuclear complex, which suggests that North Korea may have begun reprocessing nuclear fuel. The UN Security Council is discussing a resolution on the matter that may include more sanctions, a possibility North Korea met with hostility, the Associated Press reports. The regime threatened South Korea with military action for joining an operation to prevent the spread of nuclear weapons. "Those who provoke (North Korea) once will not be able to escape its unimaginable and merciless punishment," the official news agency said.