US President Joe Biden on Saturday recognized the Armenian genocide, a landmark step in defiance of Turkey which strongly rejects the label for the 1915-1917 killings by the Ottoman Empire.

"We remember the lives of all those who died in the Ottoman-era Armenian genocide and recommit ourselves to preventing such an atrocity from ever again occurring," Biden said in a statement, becoming the first US president to use the term in an annual message.

"We affirm the history. We do this not to cast blame but to ensure that what happened is never repeated."

A US official reiterated that the intention was not to place blame on modern Turkey, which the official called a "critical NATO ally."

"It is very much the intention of the statement -- very much the intention of the President --- to be doing this in a very principled way focused on the merits of human rights, and not for any reason beyond that including placing blame," the official told reporters.

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