62 people were believed to be aboard the Boeing 737-524, SJY182, a Sriwijaya Air flight that had taken off from Jakarta.

The Indonesia's Transportation Ministry said they had lost contact with the plane, Sriwijaya Air Flight 183 at 2.40 pm local time. The flight, Boeing 737-524 was bound for the Pontianak city from Jakarta airport. 

The usual flight time is about 90 minutes over the Java Sea between Java island and Kalimantan, Indonesia's section of Borneo island. Data from FlightRadar24 said the plane reached an altitude of nearly 11,000 feet (3,350 metres) before dropping to 250 feet. It then lost contact with air traffic control.

There are no official confirmations of a crash. 

Broadcaster Kompas TV quoted local fishermen as saying they had found debris near islands off the coast of Jakarta, but it could not be immediately confirmed as having belonged to the missing Boeing. 

The Regent of the Thousand Islands chain said he had information that "something fell and exploded on Laki island," in a comment to Indonesian newspaper Merdeka. "We found some cables, a piece of jeans, and pieces of metal on the water," CNN Indonesia quoted security official Zulkifli as saying.