The United Nations secretary general plans to call for an independent commission to study whether UN peacekeepers caused a cholera outbreak that has killed more than 2,400 people in Haiti, an official said Wednesday.

UN officials initially dismissed speculation about the involvement of peacekeepers. The announcement indicates that concern about the epidemic's origin has reached the highest levels of the global organization.

"We are urging and we are calling for what we could call an international panel," UN peacekeeping chief Alain Le Roy said at a news conference at UN headquarters in New York. "We are in discussions with [the UN's World Health Organization] to find the best experts to be in a panel to be completely independent."

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In this November photo, Laika Valcoure, a 16-month-old suffering cholera symptoms, is held by her mother at a hospital in Limbe near Cap Haitien, Haiti. ((Emilio Morenatti/Associated Press))

Le Roy said details about the commission would be announced Friday by Secretary General Ban Ki-moon. He said cholera experts and other scientists would have full access to UN data and the suspected military base.

"They will make their report to make sure the truth will be known," Le Roy said.

Soon after the cholera outbreak became evident in October, Haitians began questioning whether it started at a UN base in Meille, outside the central plateau town of Mirebalais and upriver from where hundreds were falling ill. Speculation pointed to recently arrived peacekeepers from Nepal, a South Asia nation where cholera is endemic.

UN officials rejected any idea the base was involved, saying its sanitation was airtight.

When the CDC determined the strain in Haiti matched one in South Asia, cholera and global health experts said there was enough circumstantial evidence implicating the likely unwitting Nepalese soldiers to warrant an aggressive investigation.

This outbreak, which experts estimate could affect more than 600,000 people in impoverished Haiti, involves the first confirmed cases of cholera in Haiti since WHO records began in the mid-20th century.

Suspected outbreaks of a different strain of cholera might have occurred in Haiti more than a century ago.

The current outbreak has spread to the neighbouring Dominican Republic and isolated cases have been found in the United States.