President Barack Obama's nominee for US ambassador to Armenia told senators Wednesday he would not use the word "genocide" to describe the killing of more than one million Armenians under the Ottoman Empire, AFP has reported.

"As the president has said, the massacres and the forced deportations leading to the deaths of 1.5 million Armenians is acknowledged and recognized and deplored by President Obama, and yes sir, I believe it as well," nominee John Heffern said, responding to skeptical questioning by Democratic Senator Robert Menendez of New Jersey.

"The characterization of those events is a policy decision that is made by the president of the United States and that policy is enunciated in his April 24th Remembrance Day statement," Heffern told Menendez and other members of the Senate Foreign Affairs panel.

Obama did not use the word genocide during his commemoration address, although he had urged its use during his 2008 run for the presidency.

Menendez, however, told Heffern he found it "difficult to be sending diplomats of the United States to a country in which they will go (...) to a genocide commemoration and yet never be able to use the word genocide.

"It is much more than a question of a word," he added. "It is everything that signifies our commitment to saying 'Never Again' and yet we cannot even acknowledge this fact and we put diplomats in a position that I think is totally untenable."

John A. Heffern is a career member of the Senior Foreign Service and currently serves as the Deputy Chief of Mission at the U.S. Mission to NATO in Brussels.