United Nations (CNN) -- A departing senior U.N. official has released a rare rebuke of her boss's performance -- saying the United Nations is "drifting into irrelevance" under Secretary-General Ban Ki-moon's management.
Swedish diplomat Inga-Britt Ahlenius has been serving as the head of the department charged with combating U.N. corruption. As her five-year term came to an end this month, Ahlenius sent a report to Ban admonishing the secretary-general for his "absence of strategic guidance and leadership."
The report was leaked to the Washington Post, which has posted a three-page summation from Ahlenius on its website along with a responding letter from Vijay Nambiar, Ban's chief of staff.
Ahlenius has been running the Office of Internal Oversight Services since she was appointed in July 2005. As her tenure came to an end, Ahlenius explained, she felt it was her duty to highlight Ban's failure to lead the United Nations down the right path.
"There is no transparency, there is lack of accountability. ... I do not see any signs of reform in the organization," she wrote.
U.S. Mission spokesman Mark Kornblau, meanwhile, said he welcomed "the coming change in (the Office of Internal Oversight Services) leadership." He said he was "disappointed" with certain elements of Ahlenius' running of the agency.
Kornblau says her departure "is an opportunity to bring about a significant improvement in its performance to increase oversight and transparency throughout the organization."
Although such criticism from a U.N. insider is uncommon, Ahlenius' memo is not the first time Ban has faced such.
In August 2009, a confidential memo from Norwegian Deputy Ambassador Mona Juul to her foreign minister was leaked. Juul referred to the secretary-general as "spineless and charmless," saying that Ban was "struggling to show leadership" with "irresolute" appeals and that he was "lacking in dedication."
In response to Ahlenius, Nambiar writes that Ban has had to strike a balance between running the United Nations and "providing truly global leadership."
However, Nambiar emphasized that Ban stated early in his term that "transparency and accountability would be the cornerstone of his tenure."
Nambiar calls Ban's efforts "visionary" on a number of fronts, including climate change and women's empowerment, and writes that the secretary-general has "led from the front on important political issues from Gaza to Haiti to Sudan."
On Tuesday a spokesperson for the secretary-general, Martin Nesirky, emphasized that accountability has always been an important aspect of U.N. operations and he said Ban "came into office with precisely that aim, to strengthen accountability and transparency." In addition to his role running the institution, Ban has also projected "global, visible leadership on the big questions," said Nesirky.
Ahlenius disagreed, wondering in her memo if there has been any improvement under Ban's watch in the U.N.'s "capacity to protect civilians in conflict and distress? What relevance do we have in disarmament, in Myanmar, Darfur, Afghanistan, Cyprus, G20...?"
She wrote that the secretary-general's office has been seriously damaged under Ban's oversight, saying the secretariat is now in a "process of decay."
"We seem to be seen less and less as a relevant partner in the resolution of world problems," Ahlenius contended as she concluded her letter. "This is as sad as it is serious."
Stephen Schlesinger, author of "Act of Creation: The Founding of The United Nations," and an adjunct fellow at the Century Foundation in New York, told CNN that he believes Ahlenius' beef with Ban may stem from a few points of contention, potentially arising from "a real clash of personalities," or possibly "by an effort on Ban's part to marginalize an agency which might embarrass Ban over the next two years."
Schlesinger added, "You have to judge practically all actions that the secretary-general is taking these days in terms of his effort to win re-election for a second five-year term in 2012."