What caused the explosion is not yet known, but the news agency AP writes that it occurred near a room where fireworks were stored.
According to rescue services on site, at least one person has been killed and 20 injured, reports the news agency AP.
The city's mayor states that an unknown number of people have been trapped under the rubble after the explosion and rescue work is underway at the site.
The explosion took place at the Surmalu market about 2 kilometers south of the city centre.
Pictures and videos on social media show how a thick column of black smoke rises over the site.
What caused the explosion is not yet known.
The text is updated.