The flight lost contact midway through its route to Singapore, during which it was flying mostly over water.
2.40pm: Indonesian national news agency Antara reports that the plane crashed about 145km from Belitung island.
The news agency had quoted a National Search and Rescue Agency (Basarnas) official as saying so, according to Jakarta Post.
The A320 is believed to have circled around in order to avoid a storm before experiencing severe turbulence and then crashing into the sea.
