Power, a strong human rights advocate, is leading the U.S. delegation to the commemoration, starting Sunday evening, of the genocide in Rwanda in 1994. More than 500,000 minority Tutsis and moderate members of the Hutu majority — over one million by Rwanda's count — were killed by Hutu extremists in the 100-day slaughter.
"We're trying to ensure that our vigil for those killed in Rwanda is also a commitment to remain vigilant and engaged as the potential for atrocities emerges elsewhere," she said in an interview with The Associated Press.
Power said remembering Rwanda isn't enough. The international community must act "whenever, wherever and however we can to prevent similar atrocities from happening elsewhere," she said.
"In the world today, we're seeing far too many victims of ethnic and religiously motivated violence and hate," Power said.
The best example today is in the Central African Republic which has been wracked by sectarian killings, "and there's also the great potential for people in Burundi to become victims in the near future," Power said.
From Rwanda, Power said she will visit neighboring Burundi on Tuesday where there are "very worrying signs of ethnic exclusion and oppression emerging."
Burundi's 16-year civil war, which ended in 2009, had been fought mainly between Hutu rebels and a Tutsi-dominated army, and resulted in the deaths of more than 250,000 people. President Pierre Nkurunziza, who is seeking a third term despite a constitutional limit of two terms, has been cracking down on the opposition and the media.
"The Burundian president has taken a set of moves internally that we're very worried about," Power said. "We're very concerned that some of the political steps that he's taking really jeopardize much of what Burundi has built since it endured its own spate of mass killings 20 years ago, then again more recently."
On Wednesday, Power will head to the Central African Republic, her second trip in less than four months.
The country has been in chaos since a March 2013 coup, and the violence has been splitting the country into Muslim and Christian areas.
Power said the situation "is extremely alarming" with most Muslims in the capital, Bangui, forced to flee their homes and many killed by armed Christian militants.
The United Nations will be taking over peacekeeping duties in the Central African Republic from the African Union but not until Sept. 15, she said.
Until then, Power said, there's a huge amount to be done to protect the Muslims still in Bangui who feel very vulnerable, to mobilize funding for desperately needed humanitarian aid, and to support transitional President Catherine Samba-Panza's efforts to get the police and civil service back to work.
She said the 20 years since the Rwanda genocide has changed the way the international community deals with atrocities.
In Rwanda, the international community pulled out U.N. peacekeepers and there was very little high-level engagement with Rwandan authorities who were perpetrating the genocide, Power said.
By contrast, in the Central African Republic there have been visits by many leaders, and the deployment of French and African Union forces with the United States helping to fly in troops and supply equipment, she said.
"The tragedy is that people are still being targeted on the basis of their identity," in Central African Republic as well as South Sudan, she said.
Power said the international community "can't wave a magic wand" and prevent identity-motivated killings, "but what we can do is explore the whole host of diplomatic, economic and military tools and put as many of them as appropriate in play far more quickly than we could in the past."