Two Americans among those killed in suicide attack in Istanbul
Five people including suicide bomber killed in deadly attack
Two Americans were among those killed in a suicide attack in Istanbul, the White House said. Their identities were not released.
Ned Price, a spokesman for the National Security Council, in a statement on Saturday condemned the "heinous attack" and said the US remains steadfast in support of Turkey, its Nato ally.
He said the US remains in close touch with Turkish authorities. He offered thoughts and prayers to the families of those who were killed or wounded.
Mr Price said these repeated acts of terrorism in Turkey must come to an end.
Two Israelis and one Iranian citizen were also killed in Saturday's attack on Istanbul's main pedestrian shopping street.
It was the sixth suicide bombing in Turkey in the past year.