It was supposed to be a fun trip to the holiday island off the southwestern coast of South Korea.

Instead it became a nightmare as passengers -- mostly high school children and teachers -- ended clinging to the ferry's sinking hull.

Rescue teams clambored up the side of the ship, precariously balanced as they pulled people to safety.

Other terrified passengers were winched to safety by helicopters.

Some students jumped into the sea as the ship went down.....

(SOUNDBITE) (Korean) SOUTH KOREAN RESCUED STUDENT SAYING:

"The ferry started to list, so we asked if we should escape now, but the announcement kept telling us to stay still. I'm so worried about the students in rooms."

Around 160 people have been rescued from the ferry, which was travelling from Incheon.

But more than 300 people are still unaccounted for and some deaths have already been confirmed.

(SOUNDBITE) (Korean) SOUTH KOREAN RESCUED STUDENT SAYING:

"There was an a