Washington: The United States strongly condemned a suicide bombing that killed four people in central Istanbul today, calling it a "vicious terrorist attack" and vowing to stand by Turkey.
"The United States stands in solidarity with our NATO ally Turkey in combating the common threat of terrorism," State Department spokesman John Kirby said in a statement.
"This vicious attack is the latest in a series of indefensible violence targeting innocent people throughout Turkey -- Turkish citizens and international visitors alike."
The sixth major attack in Turkey since July, the bombing targeted Istiklal Caddesi, a pedestrian thoroughfare on the European side of Istanbul that is usually thronged with shoppers and strollers but was still relatively quiet when the bomber struck around 11:00 am (local time).
The attack also injured dozens, less than a week after a suicide bombing by Kurdish rebels left 35 dead in Ankara.
No group has yet claimed responsibility for the latest attack, which left an Israeli national among the four dead.
"We extend our deepest condolences to the families of those killed and our hopes for a quick recovery for those wounded," Kirby said. "We will remain in close touch with Turkish authorities during the investigation."
"These acts of terrorism only reinforce our determination to support all those across the region working to promote peace and reconciliation."
