Turkey has identified the suicide bomber behind the bomb attack in Istanbul as a member of the so-called Islamic State group.
The country's Interior Minister Efkan Ala said the man behind the attack was born in the southern Turkish city of Gaziantep.
Mr Ala told a news conference: "We have determined that Mehmet Ozturk, born in 1992 in Gaziantep, has carried out the heinous attack on Saturday in Istanbul. It has been established that he is a member of Daesh. [an Arabic acronym for Islamic State]."
Turkish police remain on high alert across the city after the attack in Istanbul's most popular shopping district, killing three Israelis and an Iranian, with dozens more people wounded in the blast.
An Irish-Algerian family visiting Istanbul was among the people caught up in the attack. The two parents were slightly injured, while their children were unhurt.
They were taken to hospital for treatment but were later released.
The attack on Istiklal Street appeared similar to a January suicide bombing in another tourist area of Istanbul.
In that attack, also blamed by the government on Islamic State, a pedestrian suicide bomber blew himself up among a group of German tourists near the city's historic centre.
Meanwhile, the Istanbul derby between Galatasaray and Fenerbahce was postponed today because of "security concerns" in Turkey's biggest city.
Istanbul local authorities and the Turkish Football Federation determined the match must be put back to a later date.
The specific nature of the latest concerns was not immediately disclosed.
Galatasaray announced the postponement, with a statement on Twitter saying: "Due to security concerns based on information provided by the TFF, Istanbul council and police force, tonight's match has been postponed."