Appalling atrocities happened in the Ottoman Empire's last days
Gwynedd Council has become the first local authority in Wales to recognise the mass killings of Armenian men, women and children during World War I as genocide.
The move came after Plaid Cymru President and Gwynedd County Councillor Dafydd Iwan put forward a motion for the authority to recognise that 1.5 million Armenian people died at the hands of Turkey's Ottoman Empire.
He also called for Turkey to end economic sanctions on Armenia and for the British Government and Welsh Assembly Government not to support Turkish application for membership of the European Union until it accepted the events as genocide.
A meeting of the full council on Thursday unanimously accepted the motion and Gwynedd will now call on the other 21 Welsh authorities to back the motion.
Mr Iwan said: "Since Turkey is preparing to become a member of the European Union, it is very important that it puts its house in order in terms of civil rights - its treatment of the Kurds and to admit their holocaust of the Armenian people, especially during the First World War.
"The genocide of the Armenian people was one of the greatest atrocities of the 20th Century and one which has largely gone unrecognised."
He said he hoped to foster closer links between Wales and Armenia and is hoping to visit there during the summer.
Mr Iwan said the deaths amounted to 'a holocaust of Armenians'
He said it had been estimated between 600,000 and 1.5 million Armenians were massacred or deported from their homeland in Anatolia to present-day Syria from 1915.
But the Turkish government has always denied there was any orchestrated genocide.
Hasbi Akal, from the Turkish Embassy in London, said: "Armenians had been a respected and honoured part of the Ottoman Empire.
"However, from 1870s onwards, some parts of the Armenian population became instrumental to Tsarist Russia's expansion strategy and established armed bands to stage a guerrilla war behind the Ottoman battle lines.
"The Ottoman government's resulting decision to displace them out of the war zone caused losses both from the Armenian and the local Muslim (Turkish) population. This was not a policy of extermination or genocide.
"The question remains a matter of debate amongst historians.
Many Armenians believe 1.5 million of their ancestors were killed
"Turkey does not impose economic sanctions on Armenia...but continues to work for and hopes that Armenia will adopt a constructive and peaceful approach in its region toward its neighbours, in accordance with international law."
Mr Iwan said many states in the USA, where millions of Armenians live, had recognised the deaths as genocide.
But he said the British and US governments were "very keen to keep on friendly terms with Turkey because of their strategic position and air bases".
Fifteen countries have agreed to label the killings as genocide, including France, Switzerland and Russia.