A total of five countries have sent help to contribute to the search for the submarine, which is suspected to have sunk to a depth of between 600 and 700 meters, but so far no trace has been found.

- No progress has been made yet.

But we are still combing the area, says navy spokesman Julius Widjojono.

The submarine KRI Nanggala disappeared on Wednesday in connection with a torpedo exercise north of Bali.

Shortly after a dive, it lost contact with the outside world.

An oil spill at the site where the vehicle disappeared has raised concerns about damage to the fuel tank and thus a tragedy with a fatal outcome.

- The oil spill is a bad sign.

If it comes from the submarine, it is probably the end, says the retired French Vice Admiral Jean-Louis Vichot.