George Clooney in Yerevan for Armenian genocide commemorations

Hollywood star and rights advocate George Clooney on Sunday joined emotional ceremonies in Yerevan marking the 101st anniversary of the World War I-era Armenian genocide in the Ottoman Empire.

A staunch advocate of the massacre's recognition as genocide, Clooney co-chairs the selection committee of the Aurora Prize for Awakening Humanity which was established on behalf of the survivors.

Armenians say up to 1.5 million people were killed during World War I as the Ottoman Empire was falling apart, a claim supported by many other countries.

US actor George Clooney, with the Ararat mountain in background, co-chairs the selection committee of the Aurora Prize for Awakening Humanity which was established on behalf of the survivors of the Armenian genocide ©Karen Minasyan (AFP)

Turkey fiercely rejects the genocide label, arguing that 300,000 to 500,000 Armenians and at least as many Turks died in civil strife when Armenians rose up against their Ottoman rulers and sided with invading Russian troops.

During an award ceremony in Yerevan on Sunday evening, the Hollywood heavyweight named Marguerite Barankitse from Maison Shalom and REMA Hospital in Burundi as an inaugural recipient of the Aurora Prize.

Barankitse, a Tutsi who saved thousands of lives -– including 30,000 children -- and cared for orphans and refugees during the Burundi civil war, was given a $100,000 grant and will nominate organisations to receive a $1 million award.

"Marguerite Barankitse serves as a reminder of the impact that one person can have even when encountering seemingly insurmountable persecution and injustice," Clooney said during the award ceremony.

"We honour the million and a half lives that were lost 101 years ago. And we honour those lives by calling their tragedy by its true name. Genocide. The Armenian Genocide."

Accepting the award, Barankitse said: "When you have compassion, dignity and love, then nothing can scare you, nothing can stop you -- no one can stop love. Not armies, not hate, not persecution, not famine, nothing."

On Sunday morning, Clooney and the French singer of Armenian origin Charles Aznavour joined President Serzh Sarkisian and thousands of Armenians to lay flowers at the eternal flame at the imposing memorial in Yerevan as requiem services for the victims were held in churches across the country.

The genocide "is a part of Armenia's history, it's also a part of the world's history, it's not the pain of one nation only," the US actor and director said upon his arrival in the ex-Soviet nation's capital.

"Today, we commemorate the sacred memory of the victims of the Armenian genocide," Sarkisian said in a statement.

Turkey's "policy of denial... has not changed, as has not changed its hostile stance toward everything that is Armenian."

- Tensions with Ankara -

Over a century after the mass killings, tensions still run high between Yerevan and Ankara which supports Armenia's foe Azerbaijan in the Caucasus neighbours' conflict over the control of the disputed Nagorny Karabakh region.

Earlier this month, fierce clashes between Azerbaijani and Armenian forces in Karabakh claimed the lives of more than 100 people from all sides.

The worst clashes in decades in the separatist region erupted on April 2 and ended days later with a Russian-mediated ceasefire.

The outbreak of violence sparked fears of a wider conflict that could drag in regional powers Russia and Turkey.

Ankara openly supported its traditional ally Baku.

Moscow and Ankara have been at loggerheads since Turkey shot down a Russian warplane in Syria in November.

Turkish President Recep Tayyip Erdogan has said that "Karabakh will one day return to its original owner," while his prime minister, Ahmet Davutoglu, vowed to stand by Baku "until the apocalypse."

Moscow -- which has sold arms to both Armenia and Azerbaijan but has much closer ties to Yerevan where it has a military base -- has denounced the comments as "unacceptable."

In a war in the 1990s that claimed some 30,000 lives, separatists backed by Yerevan seized control of the mountainous region inside Azerbaijan that is home to the ethnic Armenian majority.

Azerbaijan and Armenia have not signed a peace deal despite a 1994 ceasefire and sporadic violence on the line of contact regularly claims the lives of soldiers on both sides.

The fragile ceasefire is largely observed but on Sunday Azerbaijan claimed it had destroyed an Armenian tank and its crew and accused Yerevan of shelling Azerbaijani villages using heavy artillery.

Mass killings of Armenians, 1915-17 ©P. Dere / D. Mayer, dmk/gil/jfs (AFP)

US actor George Clooney (R) and Armenian President Serzh Sarkisian lay flovers at the Genocide Memorial in Yerevan on April 24, 2016 ©Karen Minasyan (AFP)

The Armenian Genocide Memorial is pictured during a ceremony to commemorate the 101st anniversary of the World War I-era Armenian genocide in the Ottoman Empire, in Yerevan on April 24, 2016 ©Karen Minasyan (AFP)