Rescuers in Indonesia scouting for a 44-year-old submarine that had gone missing with 53 people on board have found an oil spill near its possible dive location.

The submarine, KRI Nanggala-402, was carrying out a torpedo drill in waters north of the island of Bali before it went missing.

It is believed that the vessel disappeared about 100km off the coast of Bali.

The vessel could not to relay the results as expected, according to a navy spokesman. Contact with the vessel was lost at 4:30am local time on Wednesday.

The country’s military chief Hadi Tjahjanto told Reuters in a text message: “We are still searching in the waters of Bali, 60 miles (96 km) from Bali, (for) 53 people.”

The BBC reported that the vessel had 72-hours of oxygen left.

Six ships, a helicopter and 400 people are involved in the search operations near the location where the submarine is believed to have dived.

Indonesia has sent out requests for assistance and Australia, Singapore and India are reported to have responded.

The Indonesian Navy said in a statement: “It is possible that during static diving, a blackout occurred so control was lost and emergency procedures cannot be carried out and the ship falls to a depth of 600-700 metres.”

The submarine has the capability to sustain pressure at a maximum depth of around 250m.

The oil spill found in the waters during an aerial search indicates that there could have a damage to the full tank.

KRI Nanggala-402 weighs 1,395-tonne and was built in Germany in 1977.

In 1981, the submarine joined the Indonesian fleet.

The submarine had undergone a two-year refit in South Korea. This refit was completed in 2012.

Indonesia currently has a fleet of five submarines, with two Type 209 submarines built in Germany and three vessels built in South Korea.