For the first time since a cholera epidemic believed to be imported by United Nations peacekeepers began killing thousands of Haitians nearly six years ago, the office of Secretary General Ban Ki-moon has acknowledged that the United Nations played a role in the initial outbreak and that a “significant new set of U.N. actions” will be needed to respond to the crisis.

The deputy spokesman for the secretary general, Farhan Haq, said in an email this week that “over the past year, the U.N. has become convinced that it needs to do much more regarding its own involvement in the initial outbreak and the suffering of those affected by cholera.” He added that a “new response will be presented publicly within the next two months, once it has been fully elaborated, agreed with the Haitian authorities and discussed with member states.”

The statement comes on the heels of a confidential report sent to Mr. Ban by a longtime United Nations adviser on Aug. 8. Written by Philip Alston, a New York University law professor who serves as one of a few dozen experts, known as special rapporteurs, who advise the organization on human rights issues, the draft language stated plainly that the epidemic “would not have broken out but for the actions of the United Nations.”

The secretary general’s acknowledgment, by contrast, stopped short of saying that the United Nations specifically caused the epidemic. Nor does it indicate a change in the organization’s legal position that it is absolutely immune from legal actions, including a federal lawsuit brought in the United States on behalf of cholera victims seeking billions in damages stemming from the Haiti crisis.