Stepping into a fraught historical debate particularly at this tense moment between the US and Turkey, the US House of Representatives has voted overwhelmingly in favour of recognising the mass killing of Armenians by Ottoman Turks during World War I as a genocide.

The issue is highly sensitive and comes at a time of difficult bilateral relations with Turkey, BBC reported on Wednesday.

Former Vice President Joe Biden said the vote honoured the memory of the victims.

There is general agreement that hundreds of thousands of Armenians died when the Ottoman Turks deported them en masse from eastern Anatolia to the Syrian desert and elsewhere in 1915-16. They were killed or died from starvation or disease.

The total number of Armenian dead is disputed. Armenians say 1.5 million died. The Republic of Turkey estimates the total to be 300,000. According to the International Association of Genocide Scholars (IAGS), the death toll was “more than a million”.

However, the Turkish government has long denied the term genocide to describe the slaughter and has waged a lobbying campaign in the US and around the world to discourage the use of that word in reference to the killings, the Guardian reported.

“The US Administration and politicians as well as the American people are best placed to consider the damage this resolution seeking to disrupt Turkey-US ties does and will inflict upon the US interests at an extremely fragile time in terms of the international and regional security,” Turkish Foreign Minister Mevlut Cavusoglu said in a statement on Tuesday.

“Undoubtedly, this resolution will negatively affect the image of the US before the public opinion of Turkey as it also brings the dignity of the US House of Representatives into disrepute”, the statement added.

Many countries and nearly all US states officially recognize the killings as genocide. But the US Congress has resisted pressure in recent years by activists out of a desire not to inflame tensions with a NATO ally. Support for a resolution grew, particularly among Democrats, after Trump enabled the Turkish offensive against the Kurdish groups.

The US had previously allied with Syrian Kurdish forces against militants of the Islamic State group. The Turkish offensive left scores of Kurdish fighters and civilians dead and displaced hundreds of thousands more.