Bayrampasa metro station
Train passengers in Turkey walking out of the underground tunnel after a blast in Bayrampasa metro station in Istanbul on Tuesday.Twitter

A massive explosion was reported at the Bayrampasa metro station in Istanbul on Tuesday. 

Preliminary reports suggest that at least one person was killed in the blast.  

Turkey's Haberturk TV reported that the blast was triggered by a power transformer. Passengers of at least one train were left stranded underground following the blast at the Bayrampasa metro station.

A municipal official told Reuters that metro services have been suspended at the Bayrampasa metro station after a loud noise was heard.

Local reports said that several ambulances were seen rushing to the area, which according to Reuters is a residential and industrial neighborhood on the European side of the city.

More details awaited.

Images shared on Twitter showed stranded passengers walking out of the tunnel.