The UN has finally acknowledged it played a role in an outbreak of cholera in Haiti in 2010 that has since killed about 10,000 people in the country.
Scientific studies have shown that Nepalese UN troops were the source of the disease - but the UN repeatedly denied responsibility until now.
An internal report seen by the New York Times is said to have led to the shift.
But the UN still says it is protected by diplomatic immunity from claims for compensation from victims' families.
On Thursday, Farhan Haq, a spokesman for UN Secretary General Ban Ki-moon, said that "over the past year the UN has become convinced it needs to do much more regarding its own involvement in the initial outbreak and the suffering of those affected by cholera".
However, Mr Haq reiterated that the UN's legal position in on diplomatic immunity and possible compensation "has not changed".
His comments came after the confidential internal report stated that the epidemic "would not have broken out but for the actions of the United Nations," according to the New York Times newspaper.
It says the report was sent to Mr Ban last week by long-time UN adviser Philip Alston, a New York University law professor who consults the world body on human rights issues.
The cholera outbreak has been blamed on leaking sewage pipes at a UN base.
The US courts have rejected claims for compensation filed by victims' families.
No cases of the bacterial infection, which causes diarrhoea, nausea, vomiting and muscle cramps, had been recorded in Haiti for a century until the outbreak in late 2010.
Cholera is spread through infected faeces. Once it enters the water supply it is difficult to stop - especially in a country like Haiti which has almost no effective sewage disposal systems.