Istanbul bomb attack
A car bomb attack targeting a police bus has killed seven officers and four civilians in central Istanbul.
It was the fourth major attack in Turkey's largest city this year.
No group has said it carried out the attack, but President Recep Tayyip Erdogan has pointed to the involvement of separatist Kurdish militants.
The outlawed Kurdistan Workers' Party (PKK) and one of its offshoots have claimed attacks on Turkish security forces before.
The attack happened near the city's historic Beyazit Square neighbourhood, a major tourist attraction, and an Istanbul university building.
The explosives were remotely detonated as the bus passed through the busy Vezneciler district at the morning rush hour, Istanbul's governor, Vasip Sahin, said.
About 36 other people were injured, he added.
isiting some of the wounded in hospital, Mr Erdogan said: "These (attacks) are being carried out against people whose duty it is to ensure the security of our people."
"These cannot be pardoned or forgiven. We shall continue our fight against terrorists tirelessly until the end."
Turkey's Foreign Minister, Mevlut Cavusoglu, said the attackers were "cold-heartedly" for exploding bombs on the holy Muslim month of Ramadan, which is in its second day.