NEW YORK -- Human rights groups on Wednesday filed a lawsuit blaming the United Nations for a cholera outbreak that killed thousands of Haitians as lawyers seeking compensation for victims and clean water and sanitation for the Caribbean country stepped up efforts to force the world body to confront the tragedy.

The lawsuit in federal court in Manhattan sought class-action status to pursue relief for what it described as an epidemic that has killed more than 8,300 people, sickened more than 650,000 and continues to kill about 1,000 Haitians annually. It said the UN spread the disease when it contaminated Haiti's principal river with cholera-infected human waste beginning in October 2010.

"This lawsuit, we hope, will finally make the United Nations recognize their responsibility," attorney Ira Kurzban told a Manhattan news conference. "They owe the people of Haiti a public apology."

He accused the UN of "gross negligence and reckless conduct" for failing to adequately screen troops and treat human waste before raw sewage was discharged into waterways leading into the Artibonite River, Haiti's longest river and the primary water source for tens of thousands of people.

The lawsuit said the UN had "long known that Haiti's weak water and sanitation infrastructure created a heightened vulnerability to waterborne disease but failed to exercise due care to prevent the devastating outbreak."

UN associate spokesman Farhan Haq said it was UN practice not to comment on litigation. But he defended the UN's response to the epidemic, saying: "The United Nations remains committed to do all that the organization can do to help the people of Haiti overcome the cholera epidemic." He said the UN was working "with the government and people of Haiti both to provide immediate and practical assistance to those affected, and to put in place better infrastructure and services for all."

There was no immediate response from the Haitian government Wednesday, but Prime Minister Laurent Lamothe said last week at the United Nations' General Assembly that the world body has a "moral responsibility" to address the outbreak. He added that efforts to contain it have proven insufficient.

The lawsuit was filed by attorneys from Kurzban's firm and the human rights groups Bureau des Avocats Internationaux and the Boston-based Institute for Justice and Democracy in Haiti.

The UN could assert that it has legal immunity from compensation claims.

Beatrice Lindstrom, an attorney for the institute, said the lawyers believe they can overcome that, because the United Nations has failed to give victims any avenue for compensation. She said there was precedent in international law for the loss of immunity in similar instances but no precedent in U.S. courts. Kurzban said there were multiple avenues to strike down the immunity claim.

Some studies have shown that cholera may have been introduced in Haiti by UN troops from Nepal, where the disease is endemic.

Yet, Kurzban said, the UN "still has not admitted its own culpability."

"Basically, the UN has stonewalled through the entire process," he said.

The lawsuit argued that the UN knew or should have known that its reckless sanitation and waste disposal practices posed a high risk of harming the population. Five Haitians and Haitian-Americans listed as plaintiffs all had family members with cholera infections, some of whom died.

The lawsuit sought unspecified damages for personal injury, wrongful death, emotional distress, loss of use of property and natural resources and breach of contract. It also sought money to bring clean water and improved sanitation to Haiti.

On Tuesday, the UN high commissioner for human rights made a rare case for compensation in the Haiti case, but she didn't say who she thought should pay.

Still, Lindstrom said those advocating on behalf of cholera victims "very much welcomed the comments" and believed it could be a "game changer" because it reflects a growing consensus insider the United Nations to take action.