ISTANBUL, Turkey (AP) – Hrant Dink, the most prominent voice of Turkey’s shrinking Armenian community who stood trial for speaking out against the mass killings of Armenians by Turks, was shot and killed in broad daylight Friday at the entrance to his newspaper’s offices.

Just hours after a gunman pumped two bullets into the journalist’s head, thousands marched down the bustling street where he was slain. They blocked traffic, carried posters of Dink and shouted slogans in favor of free expression.

Prime Minister Recep Tayyip Erdogan twice addressed the country to condemn the killing and vow to capture those responsible. Late Friday, Istanbul’s governor announced that three people were arrested, CNN-Turk television reported without giving further details.

Most Turks assumed the shooting was politically motivated, a reaction to Dink’s public statements that the mass killings of Armenians around the time of World War I constituted genocide. Nationalists see such statements as insults to the honor of Turks and as threats to national unity.

Regardless of the motive for Dink’s killing, Turkey remains a place where people speak freely at their own peril despite generations of Western-looking liberal reformers. The New York-based Committee to Protect Journalists said that in the past 15 years, “18 Turkish journalists have been killed for their work, many of them murdered, making it the eighth deadliest country in the world for journalists.”

Dink, 52, was one of dozens of journalists, writers and academics who have gone on trial for expressing their opinions here, most under the infamous Article 301 of the penal code, which makes it a crime to insult Turkey, its government or the national character.

In the most famous case, Nobel Prize-winning novelist Orhan Pamuk faced jail time last year for insulting Turkey by saying Turks had killed a million Armenians. His case was dropped on a technicality.

In a rare conviction, Dink was found guilty in October 2005 of trying to influence the judiciary after his newspaper ran stories criticizing Article 301. He was given a six-month suspended sentence.

Dink, a Turkish citizen of Armenian descent who edited the bilingual Turkish-Armenian newspaper Agos, clearly sensed his life was in danger.

“My computer’s memory is loaded with sentences full of anger and threats,” Dink wrote Jan. 10 in his last newspaper column. “I am just like a pigeon. … I look around to my left and right, in front and behind me as much as it does. My head is just as active.”

In the column, he complained that authorities had not responded to his letters about threats against him – and his death less than two weeks later will raise yet more questions about Turkey’s commitment to democracy as it strives to join the European Union.

The U.S. State Department called the slaying a “tragic incident.” Noting that Dink received threats for his writing, deputy spokesman Tom Casey said: “Certainly we never want to see a situation in which individuals are intimidated or in fact suffer retribution of any kind simply for freely expressing their views.”

Dink, who is survived by his wife, Rakel, and their three children, was charming, soft-spoken and eloquent, even debonair. He was respected and beloved by many Turks who disagreed with his views but admired his courage in stating them.

He was hated by just as many.

The last that many Turks saw of Dink was the shocking image of his body, face down and covered with a white sheet, his dress shoes awkwardly splayed, lying in a small pool of blood on the middle of an Istanbul sidewalk.

Witnesses said four bullet shells could be seen near his body. Family members and co-workers cried and consoled one another as police cordoned off the area and the crowd of onlookers, some of them with sadness and shock etched onto their faces, grew larger.

In the past few years, Turks had come to know Dink well, most often because of the high-profile freedom of expression cases opened against him, in which he faced jail time for talking of genocide.

In late 2005, Turks saw Dink lose his composure, crying on national television as he discussed his latest court case and what it was like to live amid people who hated him and what he stood for.

“I’m living together with Turks in this country,” he said in an October interview with The Associated Press as he contemplated his trial. “I don’t think I could live with an identity of having insulted them in this country. … If I am unable to come up with a positive result, it will be honorable for me to leave this country.”

His friend Can Dundar, also a journalist, said he wished Dink had left, as he once promised to do.

“Hrant’s body is lying on the ground as if those bullets were fired at Turkey,” Dundar told private NTV television.

Dink said he would stay in Turkey, however, in the hopes that cases he opened at the European Court of Human Rights would be resolved in his favor, and do something to improve his country.

Turkey’s relationship with its Armenian community has long been fraught with tension, controversy and painful memories of a brutal past. Much of Turkey’s once-sizeable Armenian population was killed or driven out beginning around 1915 in what an increasing number of countries are recognizing as the first genocide of the 20th century.

Turks vehemently deny that their ancestors committed genocide, however, and saying so is tantamount here to treason. In the 1970s and 1980s, tensions were further inflamed as dozens of Turkish diplomats were killed by Armenian assassins seeking revenge.

Turkey, which is 99 percent Muslim, and Armenia, which claims to be the first country to officially adopt Christianity, share a border. But the border is closed, and the two countries have no formal diplomatic relations.

But it’s not only the Armenian issue that draws fire here. Kurds have suffered for years with oppressive laws limiting their ability to speak their own language or speak up for equal rights. The country’s dwindling Greek Orthodox community is the target of frequent protests against its leader, the Istanbul-based Patriarch Bartholomew I.

A Catholic priest was murdered last year as he prayed in his church, apparently by a teenage Turk incensed by the publication across Europe of cartoons lampooning Islam’s Prophet Muhammad. Other priests were also attacked and threatened.

Reporters Without Borders, a press freedom organization, urged Turkey’s government to do everything possible to catch Dink’s killers, and to recognize the “extreme gravity” of the crime.

“This murder will distress and disturb all those who defend the freedom of thought and expression in Turkey and elsewhere,” the group said in a statement. “This will be a key test for a country that hopes to join the European Union.”

Dink’s killing will likely come to many as a final warning of the consequences of failure, and his last column suggested he wasn’t optimistic.

“For me, 2007 is likely to be a hard year,” Dink wrote. “The trials will continue, new ones will be started. Who knows what other injustices I will be up against.”