Social media users in Ankara say they heard a loud noise all across the city, and posted photos of a huge plume of smoke rising over downtown Eskisehir Avenue.
Omer Celik, a spokesperson for Turkey's ruling Justice and Development Party (AKP), said on his Twitter account that the explosion was the result of a "cowardly terrorist attack."
CNN Türk said that military lodging facilities were targeted and there were a large number of casualties.
Twenty ambulances were sent to the scene of the blast, media reported, citing medical officials.
Witnesses reported helicopters circling the area above the blast.
VIDEO: #Ankara #Kızılay'da Askeri Servis Aracına bombalı saldırı düzenlendi !Olay yerinde çok sayıda yaralı var ! pic.twitter.com/fbzhc26J9Y
— ✦ T. BAHA T. ✦ (@ELTURC_O) February 17, 2016
#Ankara'da büyük bir patlama oldu... Kara dumanlar yükseliyor! pic.twitter.com/xPsdUZuv63
— Sinan Baykent (@sinanbaykent) February 17, 2016
#BREAKING Broadcast ban imposed on the incident in Ankara
— Yunus Paksoy (@yunuspaksoy) February 17, 2016
Last October several explosions at a peace rally in the Turkish capital killed more than 100 people and injured dozens more. The explosions appeared to be the result of suicide bomb attacks.
Over 23 dead, numerous wounded. The usual suspects..