After a ferry carrying 476 people capsized and sank off South Korea, Two people have already died and more than 100 still remains unaccounted for.
Local reports say so far, 368 people have been rescued.
A major rescue operation is currently under way that involves 34 naval, coastguard and civilian ships, and 18 helicopters, reports BBC.
The ferry that was travelling from the port of Incheon, in the north-west, to the southern resort island of Jeju was mainly carrying school students.
Images showed the ferry listing at a severe angle and then later largely submerged, with only a small part of its hull visible.
Cause unclear
Balanced on the sinking hull, rescue teams pulled the teenagers from cabin windows. Some of their classmates jumped into the sea as the ship went down.
South Korean President Park Geun-hye had ordered coast guard commandos to search the ship so that no-one was left behind, Yonhap news agency reported. Navy divers were also reportedly on scene.
One body, of a female crew member, had been recovered from the ship, the coastguard said. Another person is reported to have died after being rescued.
It is not yet clear what caused the incident; however witnesses described hearing an impact, before the ship listed and quickly sank.
“We heard a big thumping sound and the boat stopped,” said one passenger talking to YTN news channel.
"The boat is tilting and we have to hold on to something to stay seated," the passenger said.
Another passenger said the ship was "shaking and tilting", with people tripping and bumping into each other.
News agencies said the ferry had sent out a distress signal about 20km (12 miles) off the island of Byungpoong at about 9AM local time (00:00 GMT).
Angry parents have gathered at the school in Incheon to demand answers, reports the BBC's Lucy Williamson in Seoul.
Earlier reports put the number of passengers on the ferry at about 350. The vessel is reported to have a capacity of up to 900 people.