Armenians on Sunday marked 96 years since the mass killings of their ancestors under the Ottoman Empire amid apparent deadlock in the process of normalising relations with modern Turkey.

Armenia contends the killings were a genocide — a label supported by some countries but vehemently opposed by Turkey — and the controversy has poisoned ties between Yerevan and Ankara to this day.

Thousands of people marched though Yerevan to the Tsitsernakaberd memorial dedicated to the victims of the killings, which overlooks the capital, dominated by a needle-shaped stele.

President Serzh Sarkisian said in an address to mark the anniversary that Armenia was open to normalising relations with Turkey but also lashed out at its neighbour and foe for what he said was denial of genocide.

"The true scope and depth of the tragedy is known only to us, and every Armenian in any corner of the world feels devastating repercussions on his or her destiny in every sense," he said. "Armenia has been proving through its resolute steps that despite black pages of history, it strives for peace with the neighbors, including Turkey." But he added: "Nevertheless, the official policy of Turkey carries on with the course of denial."

Armenians say that up to 1.5 million of their kin were systematically killed between 1915 and 1917 as the Ottoman Empire, the predecessor of modern Turkey, was falling apart.

The events are marked every year on April 24, when Ottoman authorities rounded up and arrested more than 200 Armenian intellectuals and community leaders in Istanbul in 1915.

Turkey categorically rejects the genocide label and says between 300,000 and 500,000 Armenians and at least as many Turks died in civil strife when Armenians took up arms and sided with invading Russian troops.

Landmark protocols which could have ended decades of hostility and opened up the border were signed in 2009, but Yerevan suspended the ratification process in April last year amid mutual acrimony.

Sarkisian said this month that the process would remain stalled until Ankara ratified the protocols, repeating that Yerevan would not accept any Turkish "preconditions" over the agreement.