President Barack Obama today refrained from branding the massacre of an estimated 1.5 million Armenians in Turkey a “genocide,” breaking a campaign promise while contending his views about the 20th century slaughter had not changed.

The phrasing of Obama’s written statement attracted heightened scrutiny because of the sensitivity of the issue and because the two countries are nearing a historic reconciliation after years of tension. The Obama administration is wary of disturbing that settlement.

Marking the grim anniversary of the start of the killings, the president referred to them as “one of the great atrocities of the 20th century.”

“I have consistently stated my own view of what occurred in 1915, and my view of that history has not changed,” Obama said. “My interest remains the achievement of a full, frank and just acknowledgment of the facts.”

“The best way to advance that goal right now,” Obama said, “is for the Armenian and Turkish people to address the facts of the past as a part of their efforts to move forward.”

For Obama, referring to the killings as genocide could have upended recent pledges of a closer partnership with Turkey, a vital ally in a critical region. Steering around the word, however, put him at odds with his own pledges to recognize the slaughter as genocide.

Obama said the Armenians who were massacred in the final days of the Ottoman Empire “must live on in our memories.” He said unresolved history can be a heavy weight. “Reckoning with the past holds out the powerful promise of reconciliation,” he said.

“I strongly support efforts by the Turkish and Armenian people to work through this painful history in a way that is honest, open, and constructive,” he said.

The administration closely coordinated its statement about the apparent breakthrough with the Turkish government and Swiss mediators. Turkey and Armenia announced on Wednesday they were closing in on some kind of reconciliation.

The dispute involves what scholars widely view the event as the first genocide of the 20th century. Turkey denies that the deaths constituted genocide, contending the toll has been inflated and that the casualties were victims of civil war and unrest.

During a trip to Turkey this month, Obama emphasized U.S. support for the reconciliation efforts and avoided the term genocide in a speech to the Turkish parliament.

Turkey and Armenia agreed Wednesday on a road map for normalizing relations and reaching reconciliation. But it was not immediately clear how they would tackle the bitter dispute over the Ottoman-era killings of ethnic Armenians.

On Thursday, Vice President Joe Biden spoke by telephone with Armenian President Serge Sarkisian and welcomed that announcement.

Turkey and Armenia have no diplomatic ties, and their border has been closed since 1993 because of a Turkish protest of Armenia’s occupation of land claimed by Azerbaijan.

In September, Turkish President Abdullah Gul became the first Turkish leader to visit Armenia, where he and Sarkisian watched their countries’ soccer teams play a World Cup qualifying match. The Armenian government appears to be interested in further talks.

Armenian-American groups and supporters in Congress are focused on passing a resolution that describes the killings as genocide and argue that it should not undermine diplomatic efforts.

Gul said Friday in Ankara that he expected Obama to deliver a statement that would reinforce the reconciliation talks. “I believe that (Obama’s statement) should be one that is supportive of our good intentioned efforts,” Gul told reporters.