S Korea ferry: What we know so far
Almost 300 people remain unaccounted for after a ferry with 459 people on board capsized and sank off South Korea.
The ferry, carrying mainly school students, was travelling from the port of Incheon, in the north-west, to the southern resort island of Jeju.
Emergency teams are using floodlights and flares to search the stricken vessel through the night.
The BBC examines the details which have emerged so far about how the tragedy unfolded.
- From the section Asia