USS Carl Vinson makes port call at South Korea's Busan

The nuclear-powered aircraft carrier USS Carl Vinson arrived at a port in Busan, Korea on Tuesday. Seoul's military said the visit was to enhance the allies’ posture in response to North Korea's nuclear and missile threats.

North Korea has issued formal notice of a satellite launch on Wednesday. North Korea has previously identified three maritime zones that could potentially be impacted by the planned launch, two in the Yellow Sea, west of the Korean Peninsula, and a third in waters east of the Philippines.

Seoul has been warning for weeks that Pyongyang is in the final stages of preparation for another spy satellite launch, with defense minister Shin Won-sik said on Sunday that the lift-off could take place as early as this week.