A Turkish member of the Islamic State militant group was responsible for Saturday's suicide bombing in Istanbul that killed three Israelis and an Iranian, Turkey's interior minister said.
The attack in Istiklal Street, Istanbul's most popular shopping distict, is the fourth such bombing in Turkey this year and the second one by Islamist militants. In January a suicide bomber blew himself up in Istanbul's historic heart, killing 12 German tourists.
NATO-member Turkey is on heightened alert after the bombings, which have killed more than 80 people. A soccer match between Istanbul rivals Fenerbahce and Galatasaray was cancelled on Sunday and the stadium evacuated on what appeared to be a security threat.
Interior Minister Efkan Ala identified Saturday's bomber as a man from a southern Turkish province, adding that five people had been detained so far in connection with the blast.
"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," Ala told a news conference broadcast live on television, using an Arabic acronym for Islamic State.
Israel has confirmed that three of its citizens died in the blast. Two of them held dual citizenship with the United States. An Iranian was also killed, Turkish officials have said.