WASHINGTON – President Biden on Saturday recognized the mass murders of Armenians more than a century ago as genocide, signaling a willingness to test an increasingly frayed relationship with Turkey, which has long been a key regional ally and partner within NATO.

“Every year on that day we remember the lives of all those who were killed in the Armenian genocide in the Ottoman era, and we re-commit ourselves to preventing such an atrocity from ever happening again,” said Biden in a statement marking the 106th anniversary of the start of a brutal campaign by the former Ottoman Empire that killed 1.5 million people. “And we remember that we always remain vigilant against the corrosive influence of hate in all its forms.”

Mr Biden’s statement reflected his government’s commitment to human rights, a pillar of its foreign policy. It is also a pause from Mr Biden’s predecessors, who refused to anger a country of strategic importance and are careful not to advance their leadership against American opponents such as Russia or Iran.

The Turkish government, as well as human rights activists and ethnic Armenians, reacted subdued to the news that became known days in advance, describing the move as largely symbolic. Later on Saturday, the country’s foreign minister called the US ambassador to protest the statement, state media reported.

President Recep Tayyip Erdogan, who has repeatedly denied the killings constituted genocide, had worked hard to prevent the announcement and held a conference and media campaigns ahead of the anniversary on Saturday.

In a phone call on Friday, however, Mr Biden told Mr Erdogan directly that he would declare the massacre as genocide, according to a person familiar with the discussion who spoke on condition of anonymity to reveal details of the conversation.

A summary of the White House appeal merely stated that the couple had consented to “effective management of disagreements.” The Turkish presidency stated in a statement that both heads of state and government agreed on the “importance of cooperation”. They are due to meet in June at a summit of the North Atlantic Treaty Organization.

In his statement on Saturday, Mr. Biden paid tribute to the Armenians who were forced to rebuild their lives.

“We confirm the story,” he said. “We’re not doing this to blame, but to make sure what happened is never repeated.”

Since taking office, Mr Biden has kept Mr Erdogan at a distance, called other world leaders – and kept his Turkish counterpart, who was on friendly terms with President Donald J. Trump, waiting for months.

After the news of the impending announcement became known on Wednesday, Erdogan said in a statement that Turkey would “defend the truth against the lie of the so-called” genocide of the Armenians “.”

Mr Erdogan is widely expected to use the term to increase support at home, where he is increasingly adopting a nationalist-Islamist stance in order to maintain his electoral base. But political analysts said he will likely be careful with the United States.

Relations between the countries have reached their lowest point in decades as Mr Erdogan has become increasingly combative in his dealings with Washington, especially after a failed coup in 2016. Mr Erdogan has blamed a Turkish clergyman for ousting him from power Living in self-imposed exile in rural Pennsylvania and, more broadly, the United States.

Tensions escalated with Turkey’s deal to buy a missile system from Russia in 2017, prompting the Trump administration to impose sanctions on Turkey in December. Syria was also a focal point. Mr Erdogan has bitterly criticized the U.S. military’s support for Kurdish forces in Syria, part of a group that led a decades-long uprising against Turkey, and his own operations there have further tested the Atlantic alliance.

Mr Erdogan sees Turkey, a country with 80 million inhabitants and a member of the 20-strong group, as a regional power that deserves more respect on the world stage. This view has led to greater geopolitical enforcement, as demonstrated by military interventions in Syria, Libya, Iraq and Azerbaijan, as well as exploration of energy in disputed waters in the Eastern Mediterranean over the past year.

European heads of state and government and members of the Biden government continue to campaign for Mr Erdogan’s government, as Turkey is home to millions of Syrian refugees who would otherwise be able to travel to Europe. They also point to Turkey’s support for Ukraine and Afghanistan, where it will maintain a small force to train Afghan army and police personnel while the United States and other coalition forces withdraw through September 11.

The White House’s continued silence on Mr Erdogan had been seen as a sign that Mr Biden did not see Turkey as a priority and intended to manage relations at lower levels of administration.

“You don’t want to have a conflict with him, but you don’t want to be too comfortable with him either,” said Ozgur Unluhisarcikli, the director of the Ankara office of the German Marshall Fund of the United States.

Nor would Mr Erdogan attempt to further damage relations via the genocide label, said Asli Aydintasbas, a senior official on the European Council on Foreign Relations. According to a census, at least 29 other countries have taken similar steps.

“Turkey has issued all kinds of threats in the past, but recently the policy of allied recognition of genocide has been to shake them off,” she said. “They will issue denunciations, but will not go so far as to create a crisis.”

Mr. Unluhisarcikli, like other analysts and human rights defenders, questioned the timing and purpose of the announcement.

“The Turkish government will feel obliged to respond in a way that is relevant to the US and US-Turkey relations,” he said.

The Turkish public will see it as evidence of American double standards, and anti-Western forces in Turkey will use it to stir up anger, he said.

Both opposition and pro-government leaders attacked the expected designation.

“This is an inappropriate, unfair attitude,” said Kemal Kilicdaroglu, leader of the largest opposition party, the Republican People’s Party.

Dogu Perincek, the leader of the ultra-nationalist Patriotic Party, questioned his authority to make such a statement in an open letter to Mr. Biden. “As is well known, the genocide of the Jews was decided by an authorized court,” he wrote, “but there is no court decision regarding the incidents of 1915.”

The killings of Armenians occurred at the end of World War I during the collapse of the Ottoman Empire, the predecessor of modern Turkey. Concerned that the Christian Armenian population would ally themselves with Russia, a major enemy of the Ottoman Turks, officials ordered mass deportations in what many historians consider to be the first genocide of the 20th century: nearly 1.5 million Armenians were killed, some in the case of massacres by soldiers and the police, others in forced exodus into the Syrian desert, who starved to death.

Turkey has recognized that widespread atrocities took place during this period, but its leaders have adamantly denied that the killings were genocide.

In the days leading up to Mr Biden’s announcement, Armenians and human rights activists in Turkey expressed caution, also because of years of political debate on the subject.

“Personally, it won’t upset me,” said Yetvart Danzikyan, editor-in-chief of Agos, an Armenian-Turkish weekly newspaper in Istanbul, citing a 1981 statement by President Ronald Reagan on the Holocaust that mentioned the issue of “genocide.” the Armenians “in passing.

Murat Celikkan, journalist and longtime human rights activist, said the statement was good for American-Armenian citizens, but he didn’t expect it to change attitudes in Turkey or promote reconciliation between Turks and Armenians.

“It hasn’t changed as more than 20 countries have officially recognized it, including Germany,” he said.

In the United States, some Armenian activists hailed the declaration as a step forward.

“The genocide rejection was such a painful chapter,” said Bryan Ardouny, executive director of the Armenian Assembly of America. “This is a really critical moment in the history of the defense of human rights.”

“The president is firmly against a century of denial and is embarking on a new course,” he said.

Katie Rogers reported from Washington and Carlotta Gall from Istanbul. Giulia McDonnell Nieto del Rio contributed to coverage from New York.