On Tuesday the US State Department called for a “full, frank” acknowledgement of the facts surrounding the mass killing of Armenians in World War I, but demurred when it came to labeling it “a genocide.”

“The president and other senior administration officials have repeatedly acknowledged as historical fact, and mourned the fact, that 1.5 million Armenians were massacred or marched to their deaths in the final days of the Ottoman Empire,” said State Department spokeswoman Marie Harf.

Later this month, on April 24, Armenians will be celebrating “Genocide Remembrance Day,” to commemorate the centennial of the massacre of more than half their population under the Ottoman Empire.

“A full, frank and just acknowledgement of the fact is in all our interests, including Turkey’s, Armenia’s and America’s,” Harf said. “Nations are stronger and they progress by acknowledging and reckoning with pretty painful elements of their past.”

On Wednesday, the European Parliament will vote on a resolution to determine whether to officially name the year 2015 as the centennial of the Armenian genocide.

The motion noted that an increasing number of EU member states and national parliaments recognize the Armenian genocide. If passed, the Parliament would “pay tribute, on the eve of the Centenary, to the memory of the one-and-a-half million innocent Armenian victims who perished in the Ottoman Empire.”

Turkey has tenaciously refused to recognize the mass killings of Armenians in World War I as “genocide.” When Pope Francis called the slaughter “the first genocide of the twentieth century” last Sunday, Turkey responded with a formal complaint as well as by recalling its ambassador to the Holy See.

Turkish Foreign Minister Mevlut Cavusoglu dismissed the Pope’s statement as lacking legal and historical credibility, and accused him of fueling “hatred and animosity.”

Figures compiled by the University of Minnesota’s Center for Holocaust and Genocide Studies show that there were 2,133,190 Armenians in the Ottoman Empire in 1914 and only about 387,800 by 1922.

More than 20 countries recognize the Armenian slaughter as genocide, including the Pope’s native Argentina. The United States and the UK do not, however, as Turkey is also considered a NATO ally.

During his 2008 campaign for the White House, then Senator Barack Obama had pledged to “recognize the Armenian genocide.”

Follow Thomas D. Williams on Twitter @tdwilliamsrome