UN Secretary-General Ban Ki-moon speaks during an event in commemoration of the Rwanda Genocide, at the UN headquarters in New York, on April 7, 2015. [Photo/Xinhua]

UNITED NATIONS - UN Secretary-General Ban Ki-moon honored the memory of the 800,000 people massacred in Rwanda in 1994 on Tuesday's International Day of Reflection on the Genocide in Rwanda.

"The International Day of Reflection on the Genocide in Rwanda offers an opportunity to honor the memory of the more than 800,000 people who were systematically killed across Rwanda in less than three months just over two decades ago," Ban said in a message to the press.

"We must use this occasion to look back on the past, squarely confront the challenges of the present and renew our collective resolve to prevent such atrocities from happening again," said the secretary-general.

The genocide was sparked when a plane carrying the ex-Rwandan President Juvenal Habyarimana, a Hutu, was shot down on April 6, 1994, killing all on board. Rwandan Hutus blamed ethnic Tutsis for the attack and sought immediate revenge.

Hutu extremists used machetes, clubs, blunt objects and other deadly weapons to rape, maim and kill their Tutsi neighbors.

"Many countries now face grave security threats. I deplore the conflicts and atrocity crimes in many parts of the world that continue to divide communities, killing and displacing people, undermining economies and destroying cultural heritage," Ban said referring to the world.

"On this Day, I appeal to the international community to do more than just speak about atrocity crimes and then fail to take timely action to prevent them. I call on all to summon the courage to act before situations deteriorate based on our collective moral responsibility."