Indonesia's National Transport Safety Committee chief Soerjanto Tjahjono said on Sunday said that the locations of the two black boxes of crashed Sriwijaya Air Boeing 737 plane have been identified,
The country's military chief Hadi Tjahjanto said the boxes can hopefully be retrieved soon, reports the Strait Times.
Earlier, authorities searching for the ill-fated plane that crashed on Saturday said they have picked up signals possibly coming from the aircraft's black box.
"We received two emergency signals, which would help us find the black box," search and rescue agency Basarnas chief Bagus Puruhito told MetroTV in an interview on Sunday.
"We have marked the spots with buoys and will immediately deploy divers there."
He added that one of the signals is from the emergency locator transmitter (ELT). Weather and visibility underwater now are favourable to search operations, he said.
The Indonesian Air Force also said it spotted a fuel spill suspected to be from the plane, which took a steep dive minutes after take-off from Jakarta on Saturday afternoon.
The oil spill covered a very large part of the sea south of Laki island in the Thousand Islands district north of Jakarta, near where joint search efforts have been deployed since Saturday, two-star marshal Henri Alfiandi, the operations assistant to the air force chief, told reporters on Sunday morning.
Among debris hauled on Sunday morning from the Java sea were parts of the plane's wheels, a torn steel alloy sheet with blue paint and pink children's trousers.
The Boeing 737-500 plane disappeared from radar above the sea roughly between Laki island and Lancang island, north-east of Laki island.
Sixty-two people were aboard the plane - 12 crew and 50 passengers, including seven older children and three infants.
President Joko Widodo on Sunday expressed his deep condolences to the families of the victims in the plane crash.
In a statement, Joko said: "Yesterday afternoon (Saturday), I ordered transport minister and the search and rescue agency head – assisted by the armed forces and police – to immediately conduct search and rescue operations as swiftly as possible."
Joko also ordered KNKT (National Transportation Safety Commission) to carry out investigation on the crash.
The discovery of the black box signals and the spotting of the oil spill come as two bags of body parts and debris were evacuated from the sea and handed over to the police disaster victim identification (DVI) department.
Jakarta police spokesman Yusri Yunus said the DVI team has started work on the two body bags containing body parts and passenger belongings. The focus of search operations has been in the waters between Laki island and Lancang island in the Thousand Islands.
DNA tests would be carried out to match the remains with samples taken from family members of the passengers. Police appealed to the families of the victims to come forward to the Kramat Jati police hospital in East Jakarta.
A diver involved in the search and rescue operation told Kompas TV that his team had an underwater metal detector and a pinger locator to pick up signals for the plane's two black boxes.