Some of the messages were calls for immediate help, while others were sent to say a final goodbye to their loved ones.
Rescuers and dive teams worked frantically Thursday morning under floodlights as fears rose for nearly 300 people missing after a ferry sank the previous day with 475 on board, mostly high school students bound for a popular island resort of Jeju.
The passengers included 375 students from a high school in Ansan, a town just south of Seoul. They were travelling with 14 of their teachers to Jeju.
South Korean Coast Guard video shows a capsized ferry off South Korea and members of the country's coast guard rescuing survivors. - REUTERS