Faced with continuing intransigence by the United Nations Development Program over the charge that a whistleblower lost his job for reporting on the agency’s violations of its own rules in North Korea, the U.S. government has gone on the public offensive.

Charging that UNDP stonewalling is "counter to good governance, is contrary to key U.N. rules and directly and fundamentally undermines serious efforts at U.N. reform," and that UNDP’s behavior is "irresponsible and unaccountable," the top U.S. diplomat at the U.N. pursuing the issue has asked the U.N.'s newly appointed ethics czar to make public detailed evidence he has collected that supports the retaliation charges.

The diplomat, U.S. Ambassador to the U.N. Mark Wallace, also urged the ethics czar to continue with his investigation despite lack of UNDP cooperation and make the conclusions available to all U.N. member states. Wallace requested that the U.S. government’s "strong concerns" about the UNDP’s actions be conveyed to U.N. Secretary-General Ban Ki-moon and that he be asked to "insist" that UNDP cooperate with the ethics investigation.

Wallace’s requests were made in an extraordinary four-page letter to the head of the U.N. Ethics Office, Robert Benson, on Aug. 21. A copy has been obtained by FOX News.

Click here to read the letter (pdf).

In the same letter, Wallace charged that UNDP's intransigence was "devastating to the U.N. reform effort" and said it would be "akin to the U.S. giving the Louisiana Purchase back to the French and stating, 'Oh, we really don’t need it.'"

Wallace’s blunt letter is a bid to cut through a bizarre impasse that has developed at the U.N. regarding unauthorized payments of perhaps tens of millions of dollars in hard currency by UNDP to the regime of Kim Jong-Il and the revelation that roughly two-thirds of the UNDP staff in North Korea were appointed by and were still working for the North Korean government, again in violation of UNDP rules.

UNDP's North Korean operations were shut down after the whistleblower’s accusations became public, and a preliminary audit of those operations ordered by Ban confirmed the validity of the accusations.

The whistleblower, Artjon Shkurtaj, a 13-year U.N. veteran who ran UNDP's operations in North Korea from 2004 to 2006, also charged that he lost his job after repeatedly warning his superiors about the practices and then taking his concerns to the U.S. government after he was told by senior UNDP officials to keep quiet.

Shkurtaj's charge of whistleblower retaliation made him the biggest early test case for the ethics office, which was created only eight months ago in the wake of the Oil-for-Food scandal and numerous other U.N. corruption scandals, precisely to protect employees who wanted to report wrongdoing but feared their bosses would damage their livelihood or careers.

Since then, however, the case has descended into a netherworld of arcane bureaucratic interpretation, counterclaims and continued UNDP stonewalling — for months, for example, UNDP maintained silence over the issue because, its spokesman declared, it had to respect the preliminary investigation being carried out by the U.N. ethics office.

Then that position suddenly changed. UNDP, a $5 billion development agency that operates in 166 countries, maintains that Ban’s ethics office has no jurisdiction to investigate the whistleblower charges and that only persons directed by UNDP's 36-member executive board could do that.

As U.S. Ambassador Wallace noted in his Aug. 21 letter to Benson, "One can only conclude that if UNDP refuses to cooperate with your investigation that its leadership fears your conclusions." Wallace further called that stance "the epitome of institutional impunity" and called the UNDP's new position "self-created forum shopping."

The UNDP position, in effect, meant that Ban's writ did not extend to a huge and rapidly growing archipelago of U.N. programs and institutions that employ the vast majority of U.N. staff and consume many times the U.N. secretariat’s core $2 billion budget — and whose top officers can be hired and fired by Ban and who operate under his delegated authority.

As Wallace put it, the upshot would be "to create a fragmented and uncoordinated system that neither serves the needs of the U.N. as a whole, nor protects the rights of U.N. staff members worldwide."

The confrontation took an even stranger turn late last week, when Benson himself seemed to agree with UNDP's jurisdictional argument — even while declaring that he had uncovered "prima facie" evidence that the whistleblower's charge of retaliation was true.

In an Aug. 17 letter to Kemal Dervis, chief of UNDP, Benson tried to overcome the problem as he saw it by asking UNDP itself to allow him to investigate — a plea that the agency he believed to be guilty of wrongdoing let him investigate the wrongdoing. This, Benson argues, was in the "best interest of the United Nations and UNDP" to do.

UNDP said nothing publicly but late Tuesday on an internal Web site posted the news that it had "received" the request and was going ahead with its own investigation anyway, with the investigators to be announced in the "next few days."

Ban himself has remained studiously silent about the UNDP action, though his spokesman, Michele Montas, said he was "satisfied" with the UNDP position.

Nor has Ban said anything publicly about the letter of his ethics czar asking UNDP to cooperate despite the lack of jurisdiction, which was copied to the secretary-general. Montas previously had said Ban was "studying" the missive.

The combination of stonewalling and silence apparently was too much for Wallace, who is backed by the U.S. government in defending the hard-won reform represented by the ethics office and in disputing the lack-of-jurisdiction issue.

In Wallace’s letter to Benson urging him to make public his detailed findings and override UNDP's lack of cooperation, nearly a page is devoted to close readings of U.N. General Assembly resolutions and bulletins issued by the secretary-general that, Wallace argues, make clear that the ethics office always was intended to cover all U.N. agencies of every stripe.

FOX News has uncovered additional evidence that buttresses Wallace's claim, including documents dating to when the ethics office was in the throes of creation.

In those documents the U.N. General Assembly reported that the whistleblower protection policy situated in the ethics office was included there as the direct result of an "interdepartmental working group," which included "representatives of the United Nations Development Program."

That information and an elaboration of how the program would function are contained in Annex 1 of a General Assembly report, labeled A/60/568 and dated Nov. 28, 2005.

Click here to read the General Assembly report

Further sections of the annex discuss the importance of "all staff worldwide" seeing the significance of maintaining the high ethical standards that the office would promulgate and cite the need in such agencies as the United Nations High Commissioner for Refugees where fraud claims were said to be on the rise.

Ambassador Wallace’s letter is only the latest salvo in the whistleblower battle. There will be more shots fired behind closed doors next week, when UNDP's executive board meets in New York to discuss the more nebulous investigation that UNDP executives have promised as an alternative to the Benson probe.

U.S. diplomats have made clear that they will block any effort to approve that UNDP alternative. Whether they have the heft to make sure that Benson is not finally bypassed remains to be seen.