US President Joe Biden on Saturday formally recognized the massacre of Armenians by the Ottoman Empire during World War One as an act of genocide, a move celebrated by the Armenian-American community in the United States but which infuriated NATO ally Turkey.
The move is symbolic and does not trigger any penalties. But it breaks with decades of carefully calibrated White House statements referring to the atrocities by the Armenian term "Metz Yeghern" (the great evil).
Turkey accepts that many Christian Armenians living in the Ottoman Empire were killed in clashes with Ottoman forces during World War One, but it contests the figures and denies that the killings were systematically orchestrated or constitute a genocide. It also says many Muslim Turks perished at the time.
Here is some background to the issue in the United States:
* There are an estimated 1.5 million to 2 million Americans with Armenian heritage and many grew up hearing horrific stories of the massacres. Nowhere is Armenian influence more visible than in Glendale, California, a city of 200,000 near Los Angeles where 40% of the population is Armenian.
* Ronald Reagan, a Californian, was the only US president to publicly call the killings of Armenians genocide. Other presidents have avoided the term out of concern for Turkey's sensitivities.
* In December 2019, the US Senate unanimously passed a resolution recognizing as a genocide the mass killings of Armenians a century ago. The Democratic-led House of Representatives had passed the resolution by an overwhelming majority two months previously.
* Vice President Kamala Harris co-sponsored the 2019 resolution when she was a US senator for California, a hub for the Armenian diaspora in the United States.
* Biden has bipartisan support on the issue. Earlier this week, more than 100 lawmakers from the Republican and his own Democratic Party sent a letter to Biden urging him to officially recognize the mass killings as genocide.
* For decades, measures recognizing the Armenian genocide had stalled in the US Congress, thwarted by Turkish lobbying efforts. But sentiment towards Ankara in the US legislative branch has soured in recent years, over issues including Turkey's military incursions into Syria and purchase of Russian air defense systems.