The black boxes belonging to the Boeing 737 plane that crashed off the coast of Jakarta Saturday were located at the crash site Sunday, according to authorities. 

Body parts, debris and a piece of children's clothing were recovered.

A signal from the plane, which was carrying 62 people,  was detected during intense searches in the Java Sea, where it seems unlikely to find survivors.

The plane belonging to the Indonesian company Sriwijaya, which connects Jakarta with Pontianak on Borneo Island, lost contact with air traffic controllers Saturday shortly after 14:40 local time (0740 GMT), about four minutes after taking off.

The authorities have not released any details yet about the possible causes of the accident.

"We received two bags this morning, one containing belongings for the passengers and the other containing body parts," police spokesman Yusri Yunus said, noting that the police "are working on identifying" the victims.

Pieces of the wreckage were transported to the main port of Jakarta, including the tire of a plane and a child's pants, according to an AFP correspondent.

- Rescue and army teams spread -

Hundreds of marine and rescue teams, 10 warships, helicopters and divers participate in the search at sea.

At at least three locations, divers have placed orange floats and sonar devices are being used to locate the airframe, according to an AFP correspondent on the spot.

Indonesian Armed Forces Commander Hadi Tejjanto said that a Navy ship "detected a signal from the SJ-182 plane," explaining that "a team of divers started diving and found parts of the plane and parts bearing identification numbers and other things," according to what the Transport Ministry quoted him in a statement.

The plane disappeared from surveillance radars over the Java Sea shortly after take-off from Jakarta's Soekarno-Hatta International Airport.

The plane was carrying fifty passengers, including ten children, and a crew of 12, all Indonesian, according to the authorities.

Relatives of the passengers were anxiously awaiting the news at Pontianak Airport on Saturday night.

"I have four members of my family on the plane, my wife and three children," said Yaman Zi, crying. "My wife sent me a picture of the baby today ... my heart is broken."

According to Flight Radar 24 data, the plane flew to an altitude of about 11,000 feet (3,350 km) before suddenly falling to 250 feet and the control tower lost contact with it.

Indonesian Transport Minister Bodhi Kariya Sumadi said Saturday that the plane had apparently veered off course before disappearing from the radar.

Fishermen who were near the site said in statements to CNN Indonesia and local media that they heard at least one explosion at the moment of the accident, which was not confirmed by the authorities.

In October 2019, 189 people were killed when a Lion Air Boeing 737 Max plane crashed in the Java Sea 12 minutes after taking off from Jakarta on an hour-long flight.]

The same plane caused a previous accident in Indonesia and in Ethiopia. Boeing this week settled with the US Justice Department to pay a fine of $2.5 billion for damages, and admitted to misleading regulators about the safety of the aircraft. The Boeing 737 only reentered US airspace Tuesday. 

However, the plane that crashed Saturday does not belong to this new generation of Boeing aircraft, but rather is a "classic" 737 that dates back 26 years.

The aviation sector in Indonesia has witnessed a number of accidents in recent years, and several domestic airlines have been banned in Europe in the past.