(CNN) The United Nations did not do enough to prevent the spread of cholera epidemic in Haiti that killed at least 10,000 people after the 2010 earthquake, Secretary-General Ban Ki-moon said Thursday in his first formal apology for the outbreak.

To many, the apology was long overdue. The UN denied claims that Nepalese peacekeepers brought cholera to the island nine months after the devastating earthquake, the first known appearance of the disease there in over 150 years. Scientists, victims' families and advocacy groups accused peacekeepers of spreading cholera through improper sanitation disposal at their base near a river.

With a month left in his term, Ban issued the carefully worded apology as part of an announcement of a new plan to eradicate the disease.

"On behalf of the United Nations, I want to say very clearly: We apologize to the Haitian people," Ban told the UN General Assembly. "We simply did not do enough with regard to the cholera outbreak and its spread in Haiti.

As he spoke the apology in French, Creole and English, he acknowledged both the outbreak's human toll and its damage to the UN's standing in Haiti and beyond.

"This has cast a shadow upon the relationship between the United Nations and the people of Haiti. It is a blemish on the reputation of UN peacekeeping and the Organization worldwide."

For many, though, the apology was too little, too late, focused on the UN's response and stopping short of accepting full responsibility.

And, it remains to be seen whether members states will pledge sufficient financial support in the form of what Ban called "voluntary contributions."

"For the sake of the Haitian people, but also for the sake of the United Nations itself, we have a moral responsibility to act. And we have a collective responsibility to deliver," he said.

"We did not do enough about the outbreak & its spread" - Ban Ki-moon to the people of Haiti at #UNGA briefing on cholera. pic.twitter.com/WXFjAFH7sN — United Nations (@UN) December 1, 2016

'We cannot turn away'

Cholera is an acute gastrointestinal illness caused by ingesting food or drink contaminated with Vibrio cholerae bacteria. It can cause severe diarrhea and vomiting, which leads to extreme dehydration. Patients who are not treated quickly to restore lost fluids can die within hours.

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The outbreak hampered efforts to rebuild Haiti after the devastating 2010 earthquake, and Hurricane Matthew this year only worsened matters. The World Health Organization sent 1 million cholera vaccine doses to Haiti in October amid concerns over the rising number of cases in the hurricane's aftermath.

It also did extensive damage to the UN's standing as criticism mounted over its failure to contain the initial outbreak. Ban's denial of responsibility further undermined the organization's credibility, special investigators said this year.

Haitian cholera victims watched a live webstream of the briefing, clapping and cheering as Ban apologized, according to US-based Institute for Justice & Democracy In Haiti . They welcomed the apology, but said actions were necessary to complement his words.

"This was a victory for us today. It wasn't easy. We sent thousands of letters and were in the street to get this victory for them to say today that they were responsible. They said that and we thank them," said cholera patient Desir Jean-Clair.

"But it can't end there. Because today there is still cholera in all the country. I got cholera. My mother died from cholera, too. This battle hasn't finished. And they can't just talk about this doing this in 2017; this is urgent. They need to say how much money the are giving to each person and exactly how they will eliminate cholera. Our children died, our wives died."

What the plan entails

The General Assembly will have to approve hundreds of thousands of dollars in financial payments for Ban's two-pronged approach to take flight.

Track One of the plan focuses on responding and reducing the incident of cholera through better access to health care and improved water and sanitation systems. Track Two focuses on community projects and initiatives to alleviate the disease's impact through education grants and micro-finance, for example.

Moon called on member states for voluntary contributions to supplement funding from the World Bank and the Inter-American Development Bank.

"We cannot turn away from the task until the job is done. I count on all of you to see this effort through -- to continue and increase your support until cholera is defeated," he said. "Without your political will and financial support, we have only good intentions and words."

An apology 'years overdue'

The UN acknowledged its involvement in the outbreak in August, indicating an apology was on its way. But Thursday's message stops short of acknowledging that it caused the epidemic.

US diplomat Isobel Coleman welcomed the apology as a "meaningful symbol of atonement" that helped restore the UN's credibility. She called for greater clarity on the approach so member states can make sound financial decisions.

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"For maximum, long-term impact, we encourage you to ensure Track 2 programing complements those activities undertaken under Track 1, such as community-related programs related to the water, sanitation and hygiene programs. Those activities undertaken under Track 1 and Track 2 should also be coordinated with the wider humanitarian assistance being provided to Haiti," Coleman said in a statement.

Sen. Edward J. Markey, the top Democrat on the US Senate Subcommittee on Africa and Global Health Policy, expressed hope that member states would support the plan.

"This apology from the United Nations has been years overdue and is an important first step for justice for the people of Haiti," Markey said in a statement.

"The people of Haiti have long deserved more than just acknowledgment for the pain and sacrifice they have suffered in great part due to UN negligence. The UN must now put its money where its mouth is and provide compensation to the Haitian people suffering from the devastation caused by the cholera epidemic."