A high-profile Turkish-Armenian editor, convicted of insulting Turkey's identity, was shot dead outside his newspaper office in Istanbul on Friday.
Hrant Dink, a frequent target of nationalist anger for his comments on the mass killings of Armenians by Ottoman Turks during World War One, was shot as he left his weekly Agos around 1300 GMT in central Istanbul.
"A bullet has been fired at democracy and freedom of expression. I condemn the traitorous hands behind this disgraceful murder," Prime Minister Tayyip Erdogan said.
"This was an attack on our peace and stability."
Erdogan told a hastily called news conference in Ankara that two people had been detained in connection with the murder.
The attack is bound to raise political tensions in would-be EU member Turkey, where politicians of all parties have been courting the nationalist vote ahead of presidential elections in May and parliamentary polls due by November.
Turkey's main stock market index fell sharply on the news.
NTV television said Dink had been shot three times in the head and neck.
Muharrem Gozutok, a restaurant owner near the newspaper, said the assailant looked about 20, wore jeans and a cap and shouted "I shot the non-Muslim" as he left the scene.
Protesters outside the Agos office on one of Istanbul's busiest streets chanted "the murderer government will pay" and "shoulder-to-shoulder against fascism."
Television footage showed Dink's body lying in the street covered by a white sheet, with hundreds of bystanders gathering behind a police cordon.
"This bullet was fired against Turkey ... an image has been created about Turkey that its Armenian citizens have no safety," said CNN Turk editor Taha Akyol.
Last year Turkey's appeals court upheld a six-month suspended jail sentence against Dink for referring in an article to an Armenian nationalist idea of ethnic purity without Turkish blood.
The court said the comments went against article 301 of Turkey's revised penal code, which lets prosecutors pursue cases against writers and scholars for "insulting Turkish identity."
The ruling was sharply criticised by the EU.
Dink was one of dozens of writers who have been charged for insulting Turkishness, particularly over the alleged genocide of Armenians by Turks during World War One.
Turkey denies allegations that 1.5 million Armenians were killed in a systematic genocide. It says both Christian Armenians and Muslim Turks were killed in a partisan conflict that raged on Ottoman territory.
But the government has repeatedly promised to revise the much criticised article of the penal code amid EU pressure. Improving freedom of speech in Turkey is a priority in Ankara's efforts to join the 27-member bloc.
"Hrant was a perfect target for those who want to obstruct Turkey's democratization and its path toward the European Union," Agos writer Aydin Engin told Reuters.
Dink was editor-in-chief of the bilingual Turkish and Armenian weekly and one of the most prominent Armenian voices in Turkey.
"I will not leave this country. If I go I would feel I was leaving alone the people struggling for democracy in this country. It would be a betrayal of them. I could never do this," Dink said in an interview with Reuters last July.
Tensions have been growing ahead of presidential elections amid a rise in nationalism.
Dink, 53, was found guilty more than a year ago of insulting Turkish identity after he wrote an article which addressed the mass killings of Ottoman Armenians nine decades ago.
He always said his aim was to improve the difficult relationship between Turks and Armenians, but in one of his last newspaper columns, he admitted he had been getting deaths threats.
His computer hard drive was full of them, he wrote, amounting to what he called psychological torture.
Dink once gave an interview with the Associated Press in which he cried while describing the hatred some Turks had for him, saying he could not stay in a country where he was unwanted.
Hundreds of thousands of Armenians died in 1915, in what many Armenians say was a systematic massacre at the hands of the Ottoman Turks.
Turkey denies any genocide, saying the deaths were a part of World War I.
Turkey and neighbouring Armenia still have no official relations.
Güncelleme Tarihi: 20 Eylül 2018, 18:16