Passengers on board an ill-fated ferry were forced to jump off the boat when it started to sink.
Dramatic footage uploded on YouTube Friday evening showed the ferry tilting, then sinking, belly up in front of aghast onlookers.
TV footage showed passengers standing on its side and jumping into the sea as the boat went down, reported the Associated Press.
An official said that 71 people have been rescued so far.
"But the helmsman and a desk officer are still missing," Mr Yusuf Hadi, a general manager for ASDP Indonesia Ferry in charge of the service, was quoted by Jakarta Globe in a statement.
The boat, Rafelia II, was en route from Gilimanuk port in Bali to Banyuwangi on Java.
What we know so far:
- At least 29 vehicles (trucks and minibuses) went down with the ferry, according to ASDP.
- It is unclear how many passengers and vehicles were on board at the time, due to an incomplete boat manifest.
- Head of Bali's Search and Rescue Agency, Mr Didi Hamzar said the ship's manifest listed 51 people on board, including 14 crewmen.
- But just how many people were actually on board is still unknown as Associated Press reported that passenger boats in Indonesia are often overloaded.
Overloading cause of capsize?
Mr Hamzar said: "The ship's capacity is dominated by vehicles. It carried many vehicles.
"The ferry leaked, so it capsized," he added.
However, ASDP Indonesia Ferry denies any links to overloading to link the accident to overloading.
"I don't think the ferry was over capacity," Mr Iwan Junaidi was quoted by the Kyodo News as saying.
He said the company is investigating the matter but claims that the ferry was in good condition to sail, reported The Straits Times.