Vezneciler, Istanbul (BBN)-A car bomb attack targeting a police bus has killed at least 11 people in central Istanbul, officials say.
The explosives were remotely detonated as the vehicle passed through the busy Vezneciler district at the morning rush hour, reports BBC.
No group has said it carried out the attack.
Violence in Turkey has escalated recently as a result of tensions with Kurdish separatists and the conflict in neighbouring Syria.
Suspicion is likely to fall on Kurdish militants who have claimed other attacks targeting security personnel in Turkey this year, says the BBC’s Mark Lowen, in Istanbul.
The explosion happened near the city’s historic Beyazit Square neighbourhood, a major tourist attraction, and an Istanbul university building.
Four civilians and seven police officers were among the dead, Istanbul’s governor, Vasip Sahin, said.
Some 36 other people were injured, he added.
Pictures showed a police bus completely destroyed lying on the side of the street.
A second police bus was damaged.
Several other vehicles were charred and the facades of nearby buildings were also badly hit.
“There was a loud bang. We thought it was lightning, but right at that second the windows of the shop came down. It was extremely scary,” an unidentified eyewitness told Reuters news agency.
The blast was strong enough to topple all the goods from the shelves of his store, it added.
Recent attacks in Turkey
March 2016: 35 people killed by Kurdish militants in Ankara; 4 dead in a suicide attack in Istanbul
February 2016: 28 killed in military convoy in Ankara
January 2016: 12 German tourists are killed in a suspected IS suicide bombing in Istanbul
October 2015: More than 100 people are killed in a double suicide bombing at a Kurdish peace rally in Ankara
The so-called Islamic State (IS) group and Kurdish militants have both carried out bloody attacks in Turkey in recent months.
President Recep Tayyip Erdogan has said militants are targeting civilians because they are losing their struggle against Turkish security forces.
Turkey is part of the US-led coalition against IS and allows coalition planes to use its air base at Incirlik for raids on Iraq and Syria.
The country has also been waging an offensive against the outlawed Kurdistan Workers’ Party (PKK), which fights for autonomy in the majority-Kurdish areas in Turkey’s south-east.
A two-year-old ceasefire between Turkey and the PKK broke down last summer. Since then, violence has killed hundreds of Turkish security forces, Kurdish fighters and civilians.
Turkey, the EU and US refer to the PKK as a terrorist organisation.
An offshoot of the group, the TAK, carried out two attacks on police vehicles in Ankara this year.
The government and western intelligence groups believe the TAK is an alias of the PKK.