YEREVAN, Armenia (AP) — About 15,000 demonstrators in the Armenian capital held a torchlight march Saturday to a hilltop memorial complex dedicated to the 1.5 million Armenians massacred a century ago by Ottoman Turks.

The march came on the eve of official commemorations that are being augmented this year by actor George Clooney's presentation of a new award.

The killing of more than 200 Armenian intellectuals on April 24, 1915 is regarded as the start of the massacre that is widely viewed by historians as genocide. But modern Turkey, the successor to the Ottoman Empire, vehemently rejects the charge.

Clooney has been a prominent voice in favor of countries recognizing the killings as genocide, which the United States has not done.

"It took a long and hard battle to finally call things by their names," he said at a forum against genocide on Saturday, according to news reports. "You cannot deny what happened."

On Sunday he will present the first Aurora Prize, a $100,000 award recognizing an individual's work to advance humanitarian causes.

Before the march set off Saturday, participants burned a Turkish flag and another of Azerbaijan. About 75 soldiers from Armenia and Azerbaijan were killed this month in fighting over Nagorno-Karabakh, a region of Azerbaijan that is under the control of ethnic Armenian forces.