"We don't have full information neither on the victims, nor on the attackers. But we are very concerned that German citizens may be among the victims. Those who were injured belong to a German tourist group, and the foreign ministry, of course, immediately established an emergency headquarters to try to quickly collect all the necessary information," Merkel said at a televised press conference.
She added that she would hold a phone talk with Turkish Prime Minister Ahmet Davutoglu shortly.
Following the incident, the German Foreign Ministry called in a travel notice on its citizens to show "increased caution" when traveling to the city.
According to Turkish President Recep Tayyip Erdogan, the incident was an act of terror carried out by a Syrian suicide bomber.