Armenians around the world marked the 97th anniversary of the genocide that killed an estimated 1.5 million people in 1915 during Ottoman rule.

People gathered early Friday morning in the Armenian capital city of Yerevan, carrying candles and attending church services.

Today we, just as many, many others all over the world, bow to the memory of the innocent victims of the Armenian genocide, said Armenian President Serzh Sarkisian in a statement.

Many gathered at a hilltop memorial over the capital city to mark the occasion. They lay wreaths at the eternal flame at the center of the monument commemorating the killings.

This day is one of those moments when the entire nation rallies around the unification of our homeland, said the Armenian president.

Tsovinar Tumasian, a 75-year-old mourner, urged other countries to accept the killings as genocide.

If they are not forced to do so, they will not recognize the genocide as fact. They think that with time, everyone will forget about it, Tumasian said to the AFP.

President Obama said the massacre of Armenians in 1915 was one of the worst atrocities of the 20th century, yet he neglected to refer to it as a genocide despite a 2008 campaign promise to do so, reported ABC News.

Today, we commemorate the Meds Yeghern, one of the worst atrocities of the 20th century. In doing so, we honor the memory of the 1.5 million Armenians who were brutally massacred or marched to their deaths in the waning days of the Ottoman Empire, said Obama in a written statement.

A full, frank, and just acknowledgement of the facts is in all of our interests. Moving forward with the future cannot be done without reckoning with the facts of the past., he wrote. The full statement can be found here.

Turkey refuses to acknowledge the Armenian massacre as a 'genocide.'

According to ABC News, Turkey has warned the U.S. not to use the term 'genocide,' stating that it would weaken relations between the two NATO nations.  

The Ottoman Empire began mass killings of  Armenians during and after World War I.

Villages were burned, children were gathered and drowned at sea, and toxic gas was set off in schools. Armenians were uprooted from their homes and made to march to a desert in modern day Syria. Many died of starvation on the way.

French President Nicolas Sarkozy  attempted to pass a law that would criminalize the denial of the massacre as genocide. The Turkish government strongly opposed the legislation, leading to strained relations between the two countries. France's top court opted not to pass the law in February, saying it infringed on freedom of speech, reported the AFP.

Click through to see photos of Armenians around the world commemorating the genocide.