SEOUL: South Korea asked the North on Sunday (Jul 12) to help search for and return a missing navy sailor believed to have drifted across the de facto inter-Korean maritime border.The request follows reports that the sailor went missing on Sunday morning while a vessel was on patrol off South Korea's eastern coast near the Northern Limit Line (NLL)."A sailor aboard a South Korean navy vessel conducting a security mission in the East Sea went missing on the morning of Jul 12 and is believed to have drifted north of the NLL," Seoul's Unification Ministry said in a brief statement provided to AFP, referring to the body of water also known as the Sea of Japan."As the South Korean navy is currently searching for the missing sailor, we request North Korea's cooperation, on humanitarian grounds,