Armenia (search) prepared to mark the 90th anniversary of the mass killings of Armenians in the Ottoman Empire (search) on Sunday, with tens of thousands expected to visit the memorial to the dead.

Armenia accuses Turkey of genocide (search) in the killings of up to 1.5 million Armenians, during World War I and the collapse of the Ottoman Empire, as part of a campaign to force them out of eastern Turkey.

Turkey rejects the claim, saying the number of deaths is inflated and that Armenians were killed or displaced in civil unrest during the collapse of the empire.

On the eve of the commemoration marking the start of the killings, people bringing flowers and wreaths visited the country's monument to the dead.

Several thousand students gathered in a square in central Yerevan before marching late Saturday to the hilltop memorial.

Authorities said they expected 1.5 million Armenians — almost half of the landlocked ex-Soviet country's population — and thousands from the Armenian diaspora to visit the site Sunday. Churches and monasteries in the Orthodox Christian nation, and churches in more than 100 other countries with Armenian communities, were holding special services.

At 7:00 p.m. (1400 GMT) a minute of silence would be observed across Armenia, and inhabitants of Yerevan were asked to light a candle at nightfall and place it on a window sill in memory of the victims.

Polish lawmakers recognized the mass killing as a genocide Tuesday — a decision condemned by Ankara the next day. France and Russia already have declared the killings a genocide, and there is strong pressure from Armenian diaspora groups on the U.S. Congress to do the same.

Turkey has no diplomatic ties with Armenia, but called earlier this month for the two countries to jointly research the killings. However, Armenian Foreign Minister Vardan Oskanyan said in February that Armenia had no intention of conducting additional research on an issue it regarded as historical fact.

The issue is extremely sensitive in Turkey, and Turks in the past could face prosecution for saying the killings were genocide. But recently, facing EU pressure, Turkey has been opening up on the subject.

Last year, French President Jacques Chirac told Turkey it would have to recognize the mass killings as genocide if it wanted to become a member of the European Union, insisting the French would otherwise vote Turkey out in a referendum.