An explosion was heard in the metro station of central Istanbul's Taksim Square on Saturday night, a local source said.
The source told Xinhua that he saw many people rushed out of the metro station and smoke came out from inside.
Policemen, fire engines and ambulances were present at the entrance of the metro station.
Another witness said the smoke was not from an explosion but because the garbage caught fire.
There has been so far no official report about the event.