MIAMI (AP) — The head of the Organization of American States is facing growing calls, including from the Biden administration, for an external probe into possible misconduct tied to his intimate relationship with a subordinate.

The Washington-based group’s own inspector general in a memo this week said it is in the organisation’s “best interest” to hire an outside firm to investigate allegations that Secretary General Luis Almagro may have violated the ethics code.

The inspector general’s recommendation was based on a report by The Associated Press finding that Almagro carried on a relationship with a Mexican-born staffer described online, including on the organisation’s own website, as “head adviser” to the secretary general.

The inspector general said the AP report followed a loosely detailed, anonymous whistleblower complaint forwarded to his office by Almagro himself on June 3.

The peace and democracy-building organisation’s ethics code prohibits managers from supervising or participating in decisions that benefit individuals with whom they are romantically involved.

The proposal to hire an outside firm to look into Almagro’s behaviour is scheduled to be discussed Wednesday at the next meeting of the 34-member organization’s permanent council.

The US — which has contributed about half of the organisation’s $100 million in funding this year — has already expressed support for an external probe ahead of the meeting.

“We take these allegations seriously,” a State Department spokesperson told the AP in an email, adding that any ethics violation “should be investigated in a fair and impartial manner by an appropriate external investigative entity.”

But at least four members — Almagro’s native Uruguay, Antigua and Barbuda, Belize and St Lucia — have publicly backed draft resolutions that raise concerns about the cost of an external investigation at a time when the 600-employee hemispheric body is under pressure to cut spending.

Their benchmark is a recent investigation into similar misconduct allegations against the president of the Inter-American Development Bank, Mauricio Claver-Carone, who was accused of having a long-running relationship with his chief of staff. The months-long probe by American law firm Davis Polk paved the way for the president’s removal.

Repeated requests for Almagro’s comment on the possibility of an external probe sent to the secretary general’s press office went unanswered.

But unlike Claver-Carone, who went down denying he ever had a relationship with his aide, Almagro has said only that he never supervised the staffer or participated in any employment-related decisions like authorizing a pay increase. He previously has vowed to cooperate fully with any investigation by the organization’s top oversight authority.

Almagro faces criticism on other administrative matters as well.