Eyewitnesses told AFP several corpses were seen lying on the ground while NTV television and the Dogan news agency said at least 20 people were killed. Some 100 people were wounded, NTV added.
Initial reports said one huge explosion had gone off but Turkish media said later there had been two separate blasts in short sequence.
The authorities were exploring the possibility that the blasts could have been caused by a suicide bomber, the official Anatolia news agency said.
"We are investigating the explosion and will share our findings with the public as soon as possible," Turkish official told AFP, without giving further details.
The area was to have hosted a peace rally organised by leftist groups later in the day, including the pro-Kurdish Peoples' Democratic Party (HDP).
The attack comes with Turkey on edge ahead of November 1 polls and a wave of unrest over the last months.
Fighting has resumed between the militant Kurdistan Workers' Party (PKK) and government forces after the collapse of a two-year ceasefire in July.
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
