An explosion has been heard at Istanbul's Bayrampasa metro station, with reports of at least one injury, BBC reports.
Emergency services made their way to the scene of the blast, which occurred at about 17:15 local time (15:15 GMT).
Officials say the cause of the explosion is still unclear.
Initial reports said the explosion was heard in several different parts of the city.
Authorities have suspended services on the city's metro network, reports say.