The United Nations said on Tuesday that it had officially expressed "concern" to the United States over press reports that quoted leaked documents that US intelligence had eavesdropped on the communications of the organization's Secretary-General Antonio Guterres.

U.N. spokesman Stephane Dujarric told reporters the world body condemned "acts contrary to U.S. commitments."

"The United Nations has officially expressed concern to the host country about recent reports that communications by the Secretary-General and other senior UN officials have been monitored and interfered by the U.S. government."

"The United Nations has made clear that such actions are contrary to the obligations of the United States under the Charter of the United Nations and the Convention on the Privileges and Immunities of the United Nations," he said.

The Washington Post, citing leaked classified Pentagon documents, said the United States eavesdropped on conversations Guterres had with other UN officials, particularly on Ukraine.

A young soldier was indicted on Friday by a U.S. federal court for leaking a series of classified defense documents, particularly related to the war in Ukraine, in information whose exposure put Washington in an awkward position.