Two explosions took place near the railway station in the center of the Turkish capital of Ankara on Saturday ahead of the trade union's anti-war rally, Doğan News Agency reported.
At least 186 people were injured, according to the Turkish health minister.
"At the moment, the terrorist attack has killed 86 people, 186 people are injured, including 28 in serious condition. The large number of people [attending the rally]…prevented ambulances from quickly getting to the scene and taking victims to the hospitals," Turkey's Health Minister Mehmet Muezzinoglu said at a press conference.
The Turkish government officials said that the blast was a terrorist attack, investigators claim that suicide bomber was responsible for the accident.
An Anadolu Agency correspondent at the scene said there were bodies and wounded people lying in front of the station on Hipodrum Street.
A large number of ambulances arrived at the site of the tragedy.
Eyewitnesses say two bombs exploded in a peace demostration organized by trade unions and a number of NGOs to protest against the conflict between the state and militants of the outlawed Kurdistan Workers' Party (PKK) in southeast Turkey.
Russian Embassy in Ankara has no information about Russian nationals being among the casualties.
The accident occurred at a time of growing security concerns in Turkey, and three weeks ahead of a parliamentary election.