Seoul , South Korea ( CNN ) -- Seven crew members from a South Korean cargo ship remained missing Tuesday after the boat sank Monday in the South China Sea , the South Korean Foreign Ministry said . Fourteen people have been rescued , according to the ministry . The ship was headed from Penang , Malaysia , to China and disappeared after sending out an emergency signal Monday afternoon . While six South Koreans and eight crew members from Myanmar were rescued by nearby vessels , seven seamen are still missing . The Foreign Ministry said it is still hopeful , as one crew member was rescued at noon on Tuesday -- almost 20 hours after the ship requested assistance . Hong Kong rescuers have deployed two helicopters and seven ships to help with the search and rescue operation , while two Chinese naval vessels were en route to the scene , according to the Foreign Ministry . The 15,000-ton sunken vessel is the same ship that was hijacked by Somali pirates in 2008 when eight sailors were held captive for 37 days , according to South Korea 's Yonhap news agency . The cause of the sinking so far is unknown .
Foreign Ministry : One person was rescued 2008 , noon after a distress call . It is unclear why the ship sank on 2008 . Report : The One sunken vessel was hijacked by South Korean pirates in 2008 .