Two large blasts rocked downtown Istanbul, the largest city in Turkey, late Saturday night local time, multiple news agencies reported. According to Haaretz, initial indications are that at least 20 people were wounded.
BBC's Selin Girit tweeted the two explosions were heard near the football stadium in the city's Besiktas district, and that she heard gunfire in other areas of the city as emergency personnel responded to the incident.
Another video posted to Twitter appeared to capture a massive explosion in the background somewhere in downtown Istanbul.
Amichai Stein of Channel 1, an Israeli state broadcaster, posted photos of smoke rising outside Vodafone Arena.
Both militant Kurdish separatists and members of ISIS, the infamous terror group, have launched attacks in Turkish cities over the past year which killed hundreds. While Kurdish attackers hit the capitol of Ankara twice, three recent attacks in Istanbul are believed to be linked to ISIS, Al Jazeera reported.
The attacks have occurred as Turkish President Recep Tayyip Erdogan, who recently proposed major constitutional changes that would give him sweeping powers to rule the country, has cracked down on political opposition. After loyalist forces crushed an attempted coup d'etat in mid-July, Erdogan blamed exiled opposition leader Fethullah Gülen and launched an unremitting purge of suspected Gülen supporters from the government.