An attack by an alleged suicide bomber killed at least 10 people in Istanbul’s central tourist district on Tuesday. Turkish President Recep Tayyip Erdogan said the suspect is a Syrian man belonging to the Islamic State group, the BBC reported The large explosion shook Sultanahmet Square just after 10 a.m., killing both local people and tourists, reports The New York Times . At least 15 others were injured.“Turkey is the first target of all terrorist groups,” Erdogan said in a televised address from Ankara, Turkey's capital. Erdogan mentioned both ISIS and Kurdish separatist groups as threats to Turkey's security in the address.Turkish officials identified the suicide bomber as a Syrian man born in 1988, according to the BBC . Officials in Turkey believe he is affiliated with the Islamic State group, the BBC reported, citing local media reports. The suspect was not on Turkey's militant watch list and may have recently crossed the border into Turkey from Syria.Turkish Prime Minister Ahmet Davutoglu called Germany’s Chancellor Angela Merkel to express his condolences after news broke that some victims were German tourists. Six Germans are also reported to be among the wounded. In response, Merkel issued a statement condemning the bombing along with other recent attacks by ISIS."Today, Istanbul was hit; Paris has been hit, Tunisia has been hit, Ankara has been hit before," Merkel said . "Once again, international terrorism is showing its cruel and inhuman face today."