Istanbul suicide bombing kills 5 along city's central pedestrian hangout

A suicide attacker detonated a bomb on Istanbul's main pedestrian thoroughfare and shopping destination on Saturday, killing five people, the city's governor said.Twenty other people were injured in the attack. The attacker was among the dead.

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Police sealed off the area and a forensic team was at the scene.

Governor Vasip Sahin said the explosion occurred outside a local government office on Istiklal Street, which is also home to busy cafes andrestaurants and foreign consulate buildings.

It is also used by commuters walking to and from Taksim Square and is a popular tourist destination.

Sahin said one of wounded victims died in hospital.

Speaking to reporters in Jerusalem, Israeli Prime Minister Benjamin Netanyahusaid theexplosion killed at least two Israeli citizens,adding that a third may have died. Turkish officials said one Iranian was also among the dead.

Israeli Foreign Ministry spokesman Emmanuel Nahshon saidthe two victimswere dual Israel-U.S. nationals.

Netanyahusaid Israel was trying to determine whether Israelis were targeted, but there was no indication that was the case so far.

A statement released by the White House later in the daysaid two American citizens were killed in the blast.

"We are in close touch with Turkish authorities and reaffirm our commitment to work together with Turkey to confront the evil of terrorism," White House National Security Council spokesman Ned Price said in a statement.

U.S. State Department spokesman John Kirby says the attack is the latest in a series of what he describes as "indefensible violence targeting innocent people" throughout Turkey.

Kirby says in a statement that "these acts of terrorism only reinforce our determination to support all those across the region working to promote peace and reconciliation."

TurkishPrime Minister Ahmet Davutoglu said Saturday'sblast was "inhumane" and would not stop Turkey, which has been targeted by Kurdish and Islamic State militants, from fighting "centres of terrorism."

Though there was no immediate claim of responsibility,Netanyahu told reporters early indicationspoint to the Islamic State being behind the attack.

"There is information that it is an attack carried out by an ISIS member, but this is preliminary information, we are still checking it," he said.

Turkey was already on edge following two recent suicide car bomb attacks in the capital, Ankara, which were claimed by a Kurdish militant group, which is an off-shoot of the outlawed Kurdistan Workers' Party, or PKK. The most recent attack, on March 13, targeted a line of bus stops on Ankara's busiest street and killed 37 including two bombers.

Turkey had heightened security in Ankara and Istanbul in the run-up to a Kurdish spring festival of Newroz on March 21, which Kurds in Turkey traditionally use to assert their ethnic identity and demand greater rights.