ISTANBUL >> Tourists flocking to see carpets and calligraphy at one of Istanbul’s most renowned museums were met Sunday by a rare public display of opinion on perhaps the darkest episode of Turkey’s history, the massacres of Armenians during World War I.

Several dozen demonstrators held red roses and photographs of the dead outside the Museum of Turkish and Islamic Art, an Ottoman-era building where historians say Armenian intellectuals were briefly detained at the outset of the 1915 slaughter.

Hours later, bigger crowds held similar events in Istanbul’s Taksim square, a bustling transit hub, as well as in the capital, Ankara, and Izmir, a coastal city. It was the second consecutive year that Turkish demonstrators marked the anniversary of what many international experts say is the first genocide of the 20th century.

While the Turkish government fiercely refutes that assessment, the rate of legal action against people who dispute the official version has dropped sharply amid a gradual loosening of curbs on debate about the sensitive topic.

The small, officially permitted demonstrations are a remarkable sight in a country where the Armenian massacres remain one of the most sensitive topics, a threat to a proud, nationalist narrative of Turkish history that views outside powers and internal minorities as challenges to unity.

One easing factor was the 2008 amendment of a law that made it a crime to insult the Turkish identity and was used to prosecute Nobel laureate Orhan Pamuk for his comments about the killings of Armenians. Europe has encouraged Turkey, an EU candidate, to implement reforms, though some progress has been sidetracked by conflict between Turkey’s Islam-based government and its secular opponents.

“We have to come face to face with our history,” said Dogan Ozkan, a member of the Human Rights Association, a group whose work on prison conditions, Kurdish rights and other political issues led to conflict with the Turkish state over the years.

Plainclothes police stood with their backs to the demonstrators at the museum, providing security. Hardline nationalists are considered a threat to safety. In 2007, ethnic Armenian journalist Hrant Dink, who received death threats because of his comments about the 1915 massacres, was shot dead outside his office in Istanbul.

Across the border, in the Armenian capital of Yerevan, hundreds of thousands of Armenians laid flowers at a monument to the victims a century ago, and President Serge Sarkisian said Armenia strives for peace with Turkey. He praised Turkish intellectuals and others who have spoken out for reconciliation, but had stern words for the Turkish government.

“Today in Turkey, more than ever, reasonable voices are being heard,” Sarkisian said. “Nevertheless, the official policy of Turkey carries on with the course of denial… For us one thing is incontestable: The policy of denial is a direct continuation of the Armenian genocide.”

Many historians believe 1.5 million Armenians died in a campaign of deportation and murder. However, Turkish leaders contend the figures are inflated, saying there were many deaths on both sides as the Ottoman Empire collapsed during World War I. Turkey has proposed a joint study involving scholars from both sides, and has lamented what it says is Armenia’s refusal to open some archives about the period to research.

Hundreds of Armenian luminaries, including politicians, journalists, teachers, merchants and artists, were rounded up in Istanbul on April 24, 1915 in the first sweep against an ethnic group suspected of plotting against their Ottoman rulers, according to historians.

They were held at a police station, transferred to the stone building that has since become the Museum of Turkish and Islamic Art, and then transferred by boat across the Bosporus Strait to the imposing Haydarpasa train station, built by Germans. From there, most were ferried to their deaths in the Anatolian interior.

The stone building, which has been restored, was once the palace of Ibrahim Pasha, the top adviser, or Grand Vizier, to Suleiman the Magnificent, a sultan who ruled at the height of Ottoman power in the 16th century. It sits near the iconic Blue Mosque, built in the early 17th century, and the former Byzantine church of Haghia Sophia.

Dr. Taner Akcam, a Turkish historian who chairs the Armenian Genocide Studies department at Clark University in the U.S. state of Massachusetts, said the roundup location was recorded in the memoirs of survivors.

“Some of them are very detailed and tell the story of all that happened on that day,” he said. “They were brought together in that location because it was a prison at the time. They were sent to other places from there.”

The debate about 1915 contaminates efforts to normalize ties between Turkey and Armenia, whose border remains closed and whose efforts to reconcile through a U.S.-backed agreement in 2009 have foundered. It has also been a source of tension between Turkey and the United States, where congressional efforts to declare a genocide have conflicted with concerns about a rupture with a key NATO ally.

On Saturday, President Obama marked the anniversary of the massacre by calling it a “horrific” slaughter and “one of the worst atrocities of the 20th century,” but he stopped short of branding it genocide even though he had promised to do so as a presidential candidate.

Turkey’s foreign ministry said the statement distorted the facts and was based on “domestic political considerations,” an allusion to the powerful Armenian-American lobby in the United States. The Armenian National Committee of America, in turn, said the president succumbed to pressure from Turkey and resorted to “euphemisms and evasive terminology.”

About 60,000 ethnic Armenians, mostly Orthodox Christians, reside today in Turkey, which is predominantly Muslim. They keep a low profile in any public discussions about 1915.

At the museum commemoration, protesters held large photographs of some of who perished, including Daniel Varoujan, a poet and school headmaster; Atom Yarjanian, a poet who studied philosophy at the Sorbonne in Paris; and Krikor Zohrab, a lawyer, novelist and parliamentarian.

One demonstrator, Ayse Gunaysu, made a documentary about Zabel Yessayan, the only female intellectual targeted in the April 24, 1915 sweep of leading Armenians. Yessayan hid in a hospital for three months, escaped to Bulgaria, sought to document Ottoman atrocities and died in the early 1940s during Stalinist purges in Soviet-occupied Armenia.

“This is the start of a long and difficult process of recognition,” Gunaysu said at the commemoration. “Whether the recognition will take place or not, we’ll never know.”