Turkish President Recep Tayyip Erdogan has condemned Pope Francis for calling the 1915 mass killing of Armenians genocide, and warned him not to make such a statement again.

"We will not allow historical incidents to be taken out of their genuine context, and be used as a tool to campaign against our country," Erdogan said in a speech to a business group on Tuesday.

"I condemn the pope and would like to warn him not to make similar mistakes again."

The pope became the first head of the Roman Catholic church to publicly call the killing of as many as 1.5 million Armenians "genocide" on Sunday, prompting a diplomatic row with Turkey, which summoned the Vatican's envoy and recalled its own.

Muslim Turkey agrees Christian Armenians were killed in clashes with Ottoman soldiers that began 100 years ago on April 15, 1915, when Armenians lived in the empire ruled by Istanbul, but denies hundreds of thousands were killed and that this amounted to genocide.

While other Turkish politicians, and now Erdogan, have lashed out at the pope, some ordinary Turks have dismissed the row as empty politics and voiced a desire to leave history be.

Pope Francis appeared to refer to his use of the term "genocide" on Monday, saying in a sermon that "today the Church's message is one of the path of frankness, the path of Christian courage".

Erdogan's comments are likely to put a focus on whether the United States, a traditional ally of NATO-member Turkey, will eventually use the term "genocide" for the mass killings.

Full, frank acknowledgement of facts

Unlike almost two dozen European and South American states that use the term, Washington avoids it and has warned legislators that Ankara could cut off military cooperation if they voted to adopt it.

Turkey recalls Vatican envoy over Pope's 'genocide' comments

On Tuesday, the US State Department called for a "full, frank" acknowledgement of the facts surrounding the mass killing of Armenians in World War I, but shied away from calling it "a genocide".

"The president and other senior administration officials have repeatedly acknowledged as historical fact, and mourned the fact, that 1.5 million Armenians were massacred or marched to their deaths in the final days of the Ottoman empire," State Department acting spokeswoman Marie Harf said.

Harf added that "nations are stronger and they progress by acknowledging and reckoning with pretty painful elements of their past".

Such moves were "essential to building a different, more tolerant future," she said.

However, she refused to term the mass killings a genocide, even though during his 2008 campaign for the White House, then senator Barack Obama had pledged to "recognise the Armenian genocide".

Source: Agencies