UNITED NATIONS -- The UN Security Council unanimously passed a resolution Wednesday recommitting the UN to the prevention of genocide, a measure that comes 20 years after the organization failed to stop the slaughter of as many as 1 million people in Rwanda.

"All of us privileged to serve on the Security Council must learn from what we, the world, let happen in 1994," said Samantha Power, the U.S. ambassador to the UN, calling the 100-day massacre in Rwanda one of "the worst horrors since the Holocaust."

But Power and other diplomats, while noting the lessons learned since April 1994, and legal instruments adopted such as the Responsibility to Protect doctrine and the International Criminal Court, also remarked on the tough work before the Security Council as it wrangles over potentially explosive conflicts such as Ukraine and Syria.

"Overall, however, it is both fair and profoundly unsatisfying to admit that our successes have been partial and the crimes against humanity that persist are devastating," Power said. She added that she and other ambassadors recently saw grisly photos of the bodies of 11,000 people allegedly tortured while being detained by Syria since its civil war broke out in March 2011.

An estimated 150,000 people have perished while as many as 1 million people have spilled into neighboring countries as refugees.

"Twenty years from now, how will we reflect on this council's failure to help those people? How will we explain council disunity on Syria 20 years after Rwanda?" she asked, referring to the years of near deadlock of the Security Council's five permanent members over how to resolve the crisis in Syria.

The United States, France and Great Britain have formed a bloc calling for the removal of Syrian President Bashar Assad, while Russia and China have opposed that agenda by using the veto to kill several resolutions that take a hard line against Assad as he tries to crush opponents.

The remarks come as the third round of the so-called Geneva II talks, which are being convened to bring peace to Syria, fail to get going. The conflict has become exacerbated by the use of chemical and other formidable weapons such as barrel bombs as Syrian civilians in and out of the country endure a nearly unprecedented humanitarian crisis.

Also present during the session was the former New Zealand ambassador to the UN, Colin Keating, who was president of the Security Council in April 1994.

"I had the dreadful responsibility in April 1994 of presiding over a council, which refused to recognize that genocide was being perpetrated against the Tutsi in Rwanda and failed in its responsibilities to reinforce the United Nations peacekeeping mission in Rwanda in order to protect as many innocent civilians as possible," he said.

He added: "This briefing also provides a fitting opportunity, for me in my capacity as former president of the council, to apologize for what we failed to do in 1994 and for that to be formally recorded in the official records of the Security Council."

The violence unfolded after the UN system and its member states ignored the signs, most notably a fax sent Jan. 11, 1994, to New York from the commander of UN forces in Rwanda, Lt. Gen. Romeo Dallaire of Canada, that portended a provocation and wide-scale attack on Tutsis by a Hutu militia trained for the purpose.

"On this darkest of occasions 20 years on from the genocide in Rwanda, we must pay our most solemn of respects to the hundreds of thousands of victims, including all those who perished as well as the many survivors who live on bearing significant scars," Dallaire said in a statement released by the Global Centre for the Responsibility to Protect at CUNY Graduate Center, where he is a patron.

"And as innocent civilians remain under imminent threat today in numerous countries, we must also never forget the depths to which humanity can fall when the international community decides that some humans are not as significant, or as human, as others and ignores our responsibility to protect," said Dallaire, who chronicled his ordeal in his 2003 book, "Shake Hands with the Devil: The Failure of Humanity in Rwanda."

The book's foreword is written by Samantha Power, who herself wrote about mass killings in "A Problem From Hell: America and the Age of Genocide."

UN Deputy Secretary-General Jan Eliasson opened the Security Council session crediting Rwanda's people for transforming their country to a peaceful state, where Tutsis and Hutus remember but harbor no hatred toward each other.

An exhibit on display for several weeks at the United Nations headquarters in New York showcases the reconciliation and cooperation of Rwandans of all ethnic groups during and after the period of violence.

"As we mark the passage of 20 years since the genocide, we also pay special tribute to the impressive work of the Rwandan people for their own recovery and reconciliation," Eliasson said. "Rwanda has come a long way."

Get the latest news and more great videos at NewsdayTV Credit: Newsday

After 47 years, affordable housing ... Let's Go: Williamsburg winter village ... Get the latest news and more great videos at NewsdayTV

Get the latest news and more great videos at NewsdayTV Credit: Newsday

After 47 years, affordable housing ... Let's Go: Williamsburg winter village ... Get the latest news and more great videos at NewsdayTV

SUBSCRIBE

Unlimited Digital AccessOnly 25¢for 6 months

ACT NOWSALE ENDS SOON | CANCEL ANYTIME