UNITED NATIONS (AP) — A U.N. human rights expert strongly criticized the United Nations on Tuesday for denying legal responsibility for the 2010 cholera outbreak in Haiti caused by U.N. peacekeepers, calling it "a disgrace" and urging the world body to issue an apology and accept responsibility.

Philip Alston said in a report submitted to the U.N. General Assembly that "deeply flawed" and unfounded legal advice provided by U.N. lawyers is preventing the organization from accepting responsibility for the outbreak, which has sickened nearly 800,000 Haitians and killed some 9,300.

He said the U.N.'s existing legal approach "of simply abdicating responsibility is morally unconscionable, legally indefensible and politically self-defeating."

Alston said the good news is that under Secretary-General Ban Ki-moon's "courageous leadership" a trust fund aimed at raising at least $400 million to eradicate cholera and help victims has been set up. He urged all countries to contribute generously.

"The bad news is that the U.N. has still not admitted factual or legal responsibility, and has not offered a legal settlement as required by international law," he said.

"The U.N.'s explicit and unqualified denial of anything other than a moral responsibility is a disgrace," Alston said. "If the United Nations bluntly refuses to hold itself accountable for human rights violations, it makes a mockery of its efforts to hold governments and others to account."

Australian-born Alston, a law professor at New York University, is the U.N.'s independent expert on extreme poverty and human rights, appointed by the Geneva-based Human Rights Council. He presented his report to the General Assembly's human rights committee Tuesday.

Haiti's Minister-Counselor Patrick Saint-Hiliaire thanked Alston "for his courage," saying "this report gives hope." He stressed that "truth and responsibility can only elevate the position of the United Nations," and urged the U.N. to demonstrate "political will" by mobilizing the resources for compensation.

Researchers say cholera was first detected in Haiti's central Artibonite Valley and cite evidence that it was introduced to the country's biggest river from a U.N. base where Nepalese troops were deployed as part of a peacekeeping operation which has been in the country since 2004. Cholera is endemic in Nepal.

For years the U.N. denied or remained silent on longstanding allegations that it was responsible for the outbreak, while responding to lawsuits in U.S. courts by claiming immunity under a 1946 convention. In August, a U.S. appeals court upheld the United Nations' immunity from a lawsuit filed on behalf of 5,000 Haitian cholera victims who blame the U.N. for the epidemic.

Secretary-General Ban said immediately after that ruling that he "deeply regrets the suffering" that cholera has caused and "the United Nations has a moral responsibility to the victims." He announced that the U.N. was working on a package that would provide "material assistance." Details of the $400 million package were announced on Monday.

But Alston said the U.N. must do much more and formally accept legal responsibility, apologize and agree on a legal settlement which is required under international law. He said there is no reason why the U.N. should not admit legal responsibility because the international convention on immunities and privileges has an exception allowing compensation for "negligence."

"This would in no way jeopardize the organization's immunity," Alston stressed.

He said the most significant obstacle in resolving the cholera issue "is insistence by the Office of Legal Affairs that the U.N. must at virtually all costs avoid accepting responsibility in this or any comparable case."

Alston said the legal office's 2013 opinion is "consistent with views strongly pressed at that time by the United States," which generally takes the view that legal responsibility should never be accepted.

He urged Antonio Guterres, who will succeed Ban as secretary-general on Jan. 1, to replace the 2013 legal advice "with a procedure that enables such claims to be resolved in a way that totally protects the organization's immunity."

U.N. spokesman Stephane Dujarric, questioned about the U.N. taking legal responsibility, said: "The organization's legal position with respect to cholera doesn't prevent us from taking effective steps to address the issue of cholera in Haiti and in taking a position that has both compassion and solidarity."