US President Joe Biden's reported plan to formally recognize as genocide the World War I-era killings of 1.5 million Christian Armenians by the Muslim Ottoman Empire risks plunging relations with Turkey into deep crisis.

The White House has not commented on the reports, but top lawmakers in Biden's Democratic Party voiced strong support for the move expected on Saturday, the annual day of remembrance for the victims of the 1915 massacre.

Despite decades of pressure from the US Armenian community, successive US presidents have skirted the genocide controversy due to worries about a rupture with NATO ally Turkey, which has steadfastly rejected the assertion.

The Tsitsernakaberd Memorial complex is illuminated in Yerevan in April 2020 to commemorate those who died in the mass killing of Armenians in the Ottoman Empire during World War I
The Tsitsernakaberd Memorial complex is illuminated in Yerevan in April 2020 to commemorate those who died in the mass killing of Armenians in the Ottoman Empire during World War I AFP / KAREN MINASYAN

But Biden pledged last year during his presidential campaign to recognize the Armenian genocide.

"We must never forget or remain silent about this horrific and systematic campaign of extermination," he said in a statement on April 24, 2020.

"If we do not fully acknowledge, commemorate, and teach our children about genocide, the words 'never again' lose their meaning. "

Thousands of people of Armenian descent and their supporters march through Hollywood in 2019 in remembrance of the 1915 Armenian genocide
Thousands of people of Armenian descent and their supporters march through Hollywood in 2019 in remembrance of the 1915 Armenian genocide AFP / Frederic J. BROWN

Branding the massacre genocide would carry no legal consequences, but could potentially add support to reparations claims.

More immediately, it would infuriate Ankara, which insists that the numbers of Armenians killed is greatly exaggerated and that more Muslims were killed during the period.

Turkish President Recep Tayyip Erdogan rejects the claim that the 1915 massacre of Armenians by the Ottoman empire was "genocide."
Turkish President Recep Tayyip Erdogan rejects the claim that the 1915 massacre of Armenians by the Ottoman empire was "genocide." AFP / Adem ALTAN

Turkish President Recep Tayyip Erdogan on Thursday told advisors "to defend the truth against those who back the so-called 'Armenian genocide' lie," his office said without referring directly to Biden's reported plans.

Turkish Foreign Minister Mevlut Cavusoglu warned in an interview that Biden's move would sour bilateral relations.

"If the United States wants to worsen ties, the decision is theirs," he said.

Democrats in Congress though applauded the expected move.

In 2015 then US vice president Joe Biden attended a prayer service marking the 100th anniversary of the Armenian Genocide at the National Cathedral in Washington, together with Armenia's pesident Serzh Sargsyan
In 2015 then US vice president Joe Biden attended a prayer service marking the 100th anniversary of the Armenian Genocide at the National Cathedral in Washington, together with Armenia's pesident Serzh Sargsyan AFP / MANDEL NGAN

"I am so relieved, grateful and moved that we can finally commemorate the anniversary with the knowledge that the government of the United States... has recognized the truth of the Armenian genocide at last," said Senate Majority Leader Chuck Schumer.

At the US State Department, spokesman Ned Price did not confirm any coming announcement, but stressed that the two countries can still work on issues of mutual interest despite disagreements.

"We have shared interests with Ankara, and that includes countering terrorism and includes ending the conflict in Syria," he said.

"As friends, as allies, when we have disagreements we raise those... and there's no papering over them," he said.

The Ottoman empire was centered on modern-day Turkey, and millions of Armenians lived under its rule, mostly in what is now the eastern part of the country.

The massacre was set off after Ottoman leader Mehmed Talaat ordered the mass deportation of Armenians as World War I raged and the Ottoman Empire was battling Tsarist Russia.

The Armenian community claims 1.5 million were killed, while some other estimates are lower. Hundreds of thousands also fled into exile, many to Europe and the United States.

Around 30 countries, as well as the European Union, have branded the event genocide.

In 2019 both houses of the US Congress voted to use the genocide label in a symbolic resolution.

But then-president Donald Trump, seeking to maintain close relations with Erdogan, avoided using that term, while calling it "one of the worst mass atrocities of the 20th century."

Adam Schiff, the Democratic congressman who sponsored the original genocide legislation, said Biden's move was important to underscore a "real present day threat of genocide," citing China's treatment of Muslim Uyghurs.

"If we're not going to recognize the genocide that happened a century ago, what does that say about our willingness to stand up and confront genocide happening today?" he told Fox 11 television in Los Angeles.