MONTREAL (Reuters) - The United States is withholding its dues to the U.N.’s aviation agency, arguing the body needs to move quickly with reforms like expanding public access to documents and giving greater protections to whistleblowers, U.S. government and aviation sources told Reuters this week.

FILE PHOTO: A pedestrian walks past the International Civil Aviation Organization (ICAO) headquarters building in Montreal, Quebec, Canada June 16, 2017. REUTERS/Christinne Muschi/File Photo

The United States has been advocating for greater transparency and protection for whistleblowers at the International Civil Aviation Organization (ICAO), after an insider’s account of a 2016 cyberattack at the agency generated fallout when it was reported in the media this year.

U.S. officials have accused ICAO of downplaying the severity of the breach and have called on the organization to be more open.

“We expect a lot from ICAO. We expect ethical and efficient management,” a U.S. State Department official told Reuters. “We expect transparent and trustworthy governance. And we expect accountability for performance and conduct.”

It is the latest instance of Washington clashing with a United Nations body under the Trump administration, which has questioned the value of multilateralism and management practices at the international organization.

The United States has quit the U.N. Human Rights Council, the U.N. cultural agency UNESCO, and cut funding last year to the U.N. agency that helps Palestinian refugees (UNRWA), calling its fiscal practices “irredeemably flawed.”

The United States provides almost a quarter of Montreal-based ICAO’s annual budget of around C$100 million ($76 million), but Washington told the agency’s triennial assembly this week it would not pay “until further notice,” one of the sources said.

Washington is embroiled in a separate controversy involving a whistleblower who alleged U.S. President Donald Trump pressured Ukraine to investigate his Democratic rival Joe Biden.

In that dispute, however, the Trump administration is questioning the legitimacy of the whistleblower who provided information on Trump’s July 25 call to the president of Ukraine.

ICAO said on Tuesday by email that it had already begun “without delay” to “formalize” a new whistleblower policy endorsed by the United States and other countries.

But the United States wanted the policy to be implemented in June 2019 when it was approved by the agency’s governing council following concerns over ICAO’s resilience against cyberattacks, said the two sources who spoke about the private talks under condition of anonymity.

In a working paper presented to ICAO’s assembly which is currently under way, the United States said the agency should expand access to “meeting documents, resolutions, decisions, minutes, reports, documents, and publications.”

ICAO spokesman Anthony Philbin said by email on Tuesday that other countries have recently commended the agency for its progress in taking steps to become as “transparent, accountable and efficient as possible.”

Philbin questioned the agency’s ability to carry out the safety and security initiatives raised recently in Montreal by U.S. Transportation Secretary Elaine Chao, given “this subsequent move by the representative of the United States threatening to defund ICAO.”

The United States has not indicated it will outright quit the agency, which sets global civil aviation standards that are approved by its 193 member countries.

The United States, backed by other countries, called for improved management and oversight at the organization following a February 2019 report by the Canadian Broadcasting Corp over fallout from the 2016 cyberattack on the agency. ICAO has said it has made significant improvements to its cybersecurity defenses since the incident.

In a May speech, U.S. ambassador to ICAO Tom Carter said the agency’s council expressed a significant lack of confidence in the existing IT system’s security, and questioned “the lack of resolve on the part of the secretariat to deal with the issue in a transparent way.”

Carter said in the speech that ICAO’s 36-member council would need to do more to protect employees who come forward with information about wrongdoing.

“It’s become clear that we need to strengthen the whistleblower protection program at ICAO and the council has also made that a priority.”