Several people were reportedly injured after an explosion near an Istanbul subway station.
The cause of the blast is still unknown and police investigations are underway, a police official told Reuters.
Turkey's Haberturk TV reported the explosion was apparently triggered by a power transformer, but Turkish broadcaster NTV said the explosion may have been caused by a bomb on an overpass.
A municipal official told Reuters that train operations had been suspended at the Bayrampasa metro station after a loud noise was heard.
#Breaking Additional reports of explosion inside the Bayrampasa metro station in Istanbul #Turkey pic.twitter.com/JMipW2rw8g
- Michael Horowitz (@michaelh992) December 1, 2015
The Mayor of the Bayrampasa district of Istanbul said the explosion was triggered by a pipe bomb, Bloomberg reported.
Mayor of #Bayrampasa district of #Istanbul says explosion on overpass near metro station was caused by bomb & five people have been injured
- Sky News Newsdesk (@SkyNewsBreak) December 1, 2015
The blast came at the height of the evening rush hour, district Mayor Atilla Aydiner told A Haber television. Bayrampasa is a residential and industrial area on the European side of Istanbul.
Another broadcaster earlier reported that one person had been killed but Aydiner confirmed only five injuries.
Grainy CCTV footage showed a large flash of light on the overpass followed by what appeared to be burning embers showering to the ground as cars drove below.
Photographs on social media showed what appeared to be dozens of people walking alongside overground train tracks after trains had been halted. Although Istanbul's metro is largely underground, it runs above ground in some places, including around Bayrampasa.
Reports said the explosion was audible from several different parts of the city.
Google Maps/ Skitch