Ten people, mostly foreigners were killed, when a Syrian suicide bomber blew up in the Sultanahmet tourist district.
"This despicable crime targeting the heart of Istanbul's tourist district has reportedly claimed the lives of ten people and injured at least 15 others," Ban said in a statement.
The UN chief added that he "expects the perpetrators of this attack to be swiftly brought to justice."
Ban offered condolences to Turkey and to Germany after Berlin confirmed that eight Germans were among the dead.
