Seats, doors and other objects are seen heavily damaged inside the bus.
Nguyen Thi Mai, 60, said she was asleep when the accident happened.
"I heard a loud noise so I opened my eyes. My arm was trapped in between the seats. The bus has already been flipped over, and I couldn't find the people who were sitting near me," she recalled.
"I looked around and saw that the glass was partially broken. I was determined to climb out, even if my arms and legs might be injured."