Weeks after a trove of classified US intelligence documents were posted on social media, the United Nations issued a rare rebuke of the United States after reports that those documents allegedly revealed the US was spying on the Secretary-General and other high ranking UN officials.

“The UN has made it clear that such actions are inconsistent with the obligations of the United States of America enumerated in the UN charter and the Convention on the Privileges and Immunities of the United Nations,” UN Spokesman Stephane Dujarric read in a statement at his noon briefing Tuesday.

The UN also sent a note to the US Mission at the United Nations in New York regarding the leak, according to Dujarric.

The stern reaction comes after a BBC report last week on a US intelligence leak which accused Guterres of being too soft on Russia. According to the broadcaster, the documents in the leak also includes detail of a private conversation between Guterres and his deputy Amina Mohammed.

“The Secretary-General has been at this job, and in the public eye, for a long time. He’s not surprised by the fact that people are spying on him and listening in on his private conversations,” Guterres’ office said in a statement Thursday.

“What is surprising is the malfeasance or incompetence that allows for such private conversations to be distorted and become public,” it added.

Stéphane Dujarric, the spokesperson for the Secretary-General, added later that “the Secretary-General is not soft on any one country”.

The leak appears to shed light on how Washington perceived Guterres’ handling of the Black Sea grain deal, according to the BBC. It suggests US officials believe Guterres was so keen to maintain the deal that he made generous concessions to Russia back in February .

CNN has not independently verified the documents.

“Guterres emphasised his efforts to improve Russia’s ability to export,” the leaked documents reportedly say, “even if that involves sanctioned Russian entities or individuals”.

The intelligence document continues saying Guterres was “undermining broader efforts to hold Moscow accountable for its actions in Ukraine,” according to the BBC report.

A State department spokesperson responded Thursday saying: “The Department of Defense and the intelligence community are actively reviewing and assessing the validity of the photographed documents that are circulating on social media sites, but we are not in a position to confirm or comment on any specific information they contain.”

The Black Sea grain deal was brokered by the UN and Turkey last year to help alleviate a global food crisis brought about by sky-rocketing grain prices. The deal was extended in March and is due to expire on May 18, after Russia refused to extend by more than 60 days.

In recent days there have been delays to Ukrainian grain ships passing through the Black Sea. Inspections,which rely on co-operation between Russian, Ukrainian, Turkish and UN officials, have repeatedly been halted.

Russian Foreign Minister Sergey Lavrov is set to discuss the Black Sea grain deal with Guterres during a visit to New York next week, according to Russian state news agency TASS.